Brake Reaction Time Research Articles

Doctor when can I drive? Braking response after knee arthroplasty: A systematic review & meta-analysis of brake reaction time

BackgroundThere is limited evidence available on return to driving for patients undergoing knee arthroplasty (KA). Primarily, surgeons have used brake reaction time as a surrogate measure of safe return to driving. The purpose of this study was to review existing literature and provide guidance on the recovery of braking performance following knee arthroplasty. MethodsA literature search was performed for prospective studies on driving after KA. Two reviewers screened citations for inclusion, assessed methodological quality, and extracted data. Values for total brake reaction-time (TBRT), movement-time (MT), reaction-time (RT), and braking-force (BF) were included for meta-analysis. ResultsTwelve studies with 368 subjects were identified. TBRT, RT, MT, and BF relative to preoperative baseline were assessed. Meta-analysis of TBRT showed a significant improvement from preoperative baseline at 3 months & 1 year (p = 0.003 & p = 0.0001). MT showed a significant increase at 2 and 4 weeks (p = 0.00001 & p = 0.03) before returning to no being significantly different at 6 weeks and beyond. In contrast RTs were noted to improve significantly 2 weeks (p = 0.006), 4 weeks (p = 0.03), and 1 year (p = 0.0002). ConclusionMeta-analysis showed no significant difference in TBRT up until 3 months. RT increased significantly post-operatively suggesting it is not a reliable indicator. MT in contrast was significantly decreased post KA and may represent a more reliable measure of braking performance post KA. Surgeons should consider these recommendations and other patient factors that determine fitness to drive prior to advising their patients on a safe to return to driving.

Driving ability after right-sided inguinal hernia surgery.

To investigate driving ability (brake reaction time, BRT) after right-sided hernia repair. It was assumed that postoperatively BRT would be impaired as compared to the preoperative reference and healthy controls. BRT was prospectively collected from 30 patients undergoing hernia repair [Lichtenstein or total extraperitoneal endoscopic procedure (TEP)]. BRT was measured with a driving simulator preoperatively and on postoperative days 2 and 14. After receiving a visual stimulus, the patients had to apply the brake pedal with 160N. The average of ten runs was used as the patient's BRT value. Thirty patients completed all measurements. In the Lichtenstein group, BRT was significantly impaired as compared to the patient's preoperative values (p = 0.021). Two weeks after surgery BRT had returned to the preoperative level (p = 0.859). BRT in the Lichtenstein group was also significantly impaired 2 days postoperatively as compared to the BRT of 60 healthy controls (p = 0.001). In the TEP group, no impaired BRT was detected. Based on our finding of significantly impaired BRT in patients following right-sided Lichtenstein hernia repair, it seems wise to recommend that such patients refrain from driving for 2 weeks after surgery. No such impairment was found in patients following TEP surgery. Consequently, it is deemed safe for them to resume driving 2 days after the procedure.

When is it Safe to Resume Driving Following a Right-Sided Hip or Knee Replacement?

Background: Returning to safe driving is an essential aspect of the rehabilitation following total hip (THR) or total knee replacement (TKR). Making an emergency stop has been used in the past as the main criteria to assess fitness to drive following surgery.Methods: We have tested the Total Brake Reaction Time (TBRT) before surgery and at different intervals post-surgery (1,2,4 and 6 weeks) using a driving simulator. A return to baseline TBRT was used as the criteria for safe driving status.Results: Overall, 22 patients (11 males and 11 females), 14 in the THR and 8 in the TKR group. The median recovery time for the THR group was two weeks compared to 4.4 weeks for the TKR group (p<0.034). The overall failure rate of return to baseline was 14.3% for THRs and 62.5% for TKRs. Females had a significantly slower mean baseline TBRT (504ms) compared to males (414ms) (p<0.046) but had a faster median recovery time of 2 weeks compared to 3.3 weeks for males (p<0.72). However, we found a higher failure rate of return to baseline of 45.5% for females compared to 18.2% for males.Conclusion: Due to a wide variation in the recovery of safe driving ability, we recommend that patients refrain from driving for 2-4 weeks following a hip replacement and 6-8 weeks following a knee replacement.

Analysis of driving simulator performance for post-call orthopaedic surgery residents

PurposeDespite the associations between workhours, fatigue and motor vehicle accidents, driving abilities for residents post-call have been infrequently analysed. Our purpose was to compare orthopaedic surgery resident performance on a...

Doctor when can I drive? A systematic review and meta-analysis of return to driving after total hip arthroplasty.

Advice given to patients on driving resumption after total hip arthroplasty (THA) is inconsistent. Due to a lack of clear guidelines, surgeons' recommendations range between 4-8 weeks after surgery to resume driving. Delays in driving return can have detrimental social and economic impact. However, it is important to ensure patients only resume driving once safe. This study presents a systematic review and meta-analysis of driving simulation studies after THA to establish when patients can safely return to driving postoperatively. A systematic review and meta-analysis using PRISMA guidelines was undertaken. Titles and abstracts were screened for inclusion, data was extracted, and studies assessed for bias risk. Review Manager, was used for statistical analysis. Values for brake reaction time (BRT) were included for meta-analysis. 14 articles met the inclusion criteria. Of these, 7 measured BRT and were included in the meta-analysis. Pooled means of both right and left THA showed BRT around or above preoperative baseline at 1 week, 2 weeks and 3 weeks, and below baseline at 6 weeks, 12 weeks, 32 weeks and 52 weeks. Of these, the pooled means at 6, 32, and 52 weeks were significant (p < 0.05).Studies not meeting meta-analysis inclusion criteria were included in a qualitative analysis, examining self-reported postoperative driving return times which ranged from 6 days to over a year or in rare cases, never. Majority of patients (n = 960) self-reported driving return within approximately 6 weeks (pooling of mean values 32.9 days). The mean return to driving time recommended in the literature was 4.5 weeks. Based upon BRT meta-analysis, a return to baseline braking performance was noted at 6 weeks postoperatively. However, driving is a complex skill, and patient recommendation should be individualised based on factors such as vehicle transmission type, THA technique, surgical side, medication and comorbidities.

Break Reaction Time after Conservatively Treated Ligament Ruptures of the Ankle

BackgroundAnkle sprain lesions are the most common ligament lesions in humans. One particularly dangerous consequence of this pathology is an inability to quickly and sufficiently depress the brake pedal when driving a car. The high incidence of the lesion, in the context of a society that is highly automobile-dependent, makes the question “When can a patient safely drive a car again?” of particular socioeconomic importance. Hypothesis/PurposeThough orthopaedic physicians are often confronted with this question, finding an answer in the sparse literature on the topic proves difficult. This study aims to provide a definitive answer to this question. Study DesignProspective Case Control Study. Methods30 patients with grad II and III ligament injuries of the right ankle (18 women, 12 men) and 30 healthy volunteers (19 women, 11 men) participated in this study. Brake reaction time (BRT) was assessed using a previously reported custom-made driving simulator. BRT was assessed two, four and six weeks after injury. Simultaneously the American Orthopedic Foot and Ankle Society Ankle Hindfoot Score (AOFAS-AHS) was assessed. ResultsTwo weeks after the incident, the patients’ BRT measured 690.6±186.2ms. Four weeks after the incident, the BRT improved to 551.8±137.3ms (p<0.001). Compared to the healthy controls’ BRT (553.6±118.6ms), there were no significant differences 4 weeks after the injury (p=0.473). At this time, the BRT of both groups was also well below (i.e. faster) than the recommendations of road authorities (700-1500ms). An AOFAS-AHS score of more than 80 points correlated with a sufficient BRT. ConclusionsFour weeks post injury, patients generally had a sufficient BRT to drive in traffic safely. Some patients could achieve sufficient BRTs at an earlier stage. All patients with sufficient BRTs had an AOFAS-AHS score of ≥81 points. The AOFAS-AHS score can therefore be regarded as an adequate screening tool to evaluate which patients are ready to safely operate motor vehicles earlier.

The Impacts of Warning Release Time and Speed Limit on Driving Behaviour and Pedestrian-Vehicle Collision Rate on Side-parking Road

As we all know, pedestrian-vehicle collisions would cause serious damage to us, especially those caused by blind spots. This study focused on collisions happen in the side- parking road, using a driving simulator to design scenarios. After finishing the experiment, we selected some variables to describe the driver’s driving behaviour, including brake reaction time, warning-to-brake time, and maximum deceleration. To verify the effectiveness of the audio warning system, the collision rate was also discussed. It was found that warning release time has significant effects with all the variables, and gender has significant effects with brake reaction time and warning-to-brake time, while the speed limit only influences maximum deceleration. Collision rate was affected by speed limit and warning release time, which decreased with the increase of speed limit and the late release of warning. It is recommended to set the warning release time to 4s before the collision. On the other hand, it is necessary to select a proper speed limit on the side-parking roads, and it is better to set it under 30km/h to reduce the probability of pedestrian-vehicle collision.

Effectiveness of the compensatory strategy adopted by older drivers: Difference between professional and non-professional drivers

It has been a controversial issue for the effect of ageing population on driving safety. Apparently, drivers’ physiological and cognitive performances deteriorate with age. However, older drivers may compensate for the elevated risk by adjusting their behaviors, known as compensatory strategy. Despite the extensive research on this topic, the compensatory strategy of older professional drivers is not well understood since many studies focused on the differences in compensatory behavior between older and young drivers. Professional drivers tend to be more skillful and able to cope with the unfavorable driving environments, thus presenting a higher capability to mitigate the risk. This study attempts to examine the compensatory behavior and its safety effect amongst older professional drivers, as compared to those of older non-professional drivers, using the driving simulator approach. In the driving simulator experiment, participants were asked to follow a leading vehicle for one hour, and two sudden brake events were presented. 41 (mid-aged and older) drivers completed the driving tests. Each participant was required to complete a car-following test, either under high or low traffic flow conditions. Performance indicators include driving capability (i.e. lateral control, longitudinal control, and brake reaction time) and compensatory behavior (i.e. average speed, and time headway). Additionally, two modified traffic conflict measures: time exposed time-to-collision (TET) and time integrated time-to-collision (TIT) are applied to indicate the traffic conflict risk. The random parameter Tobit models were estimated to measure the association between conflict risk and driver attributes, and random intercept models were used to assess other driving performance indicators. Results show that despite the impaired lateral control performance and longer brake reaction time of older drivers, the likelihood of severe traffic conflict of older drivers is lower than that of mid-aged drivers. Furthermore, though both older professional and older non-professional drivers adopted longer time headway, the reduction in the risk of severe traffic conflict is more profound among the older professional drivers. Such findings suggest that older professional drivers are more capable of mitigating the possible collision risk by adopting the compensatory strategy, as compared to older non-professional drivers. This justifies the existence of compound effect by the compensatory strategy of older driver and better driving skills of professional driver. This research provides useful insights into driver training and management strategies for employers, as older drivers would become a major cohort in the transportation industry.

Intra- and Inter-Session Reliability of Methods for Measuring Reaction Time in Participants with and without Patellofemoral Pain Syndrome.

To evaluate the relative and absolute reliability of reaction time measuring methods during different conditions in participants with and without patellofemoral pain syndrome (PFPS). 30 patients with PFPS and 30 healthy controls were recruited in the present study. The upper extremity reaction time, upper extremity error rate, involved and non-involved lower extremity braking reaction times, and involved and non-involved knee extension reaction times were measured. Each condition was repeated three times, 2 sessions with a 5-7 days interval. The intra-session reliability was evaluated in three-trial (A), second- and third-trial (B) modes. In addition, the inter-session reliability was evaluated in mode A, mode B, and best score (C) mode. The result of inter-session reliability of mode A showed that all measurements except upper extremity reaction time in PFPS group showed high to very high relative reliability (ICC: 0.74-0.94). In mode B, all measurements except non-involved knee extension reaction time in PFPS group showed high to very high relative reliability (ICC: 0.71-0.93). In mode C, all measurements showed high to very high relative reliability (ICC: 0.70-0.94) except upper extremity error rate and non-involved knee extension reaction time in PFPS group. The result of intra-session reliability showed that all measurements had high to very high relative reliability (ICC: 0.78-0.94) in mode A. In mode B, all measurements showed high to very high relative reliability (0.78-0.94). The braking time seems more reliable than other reaction time tasks. In addition, the results showed that mode A is more reliable than other modes. The newly designed package is a reliable tool to measure the knee extension reaction time in patients with knee musculoskeletal disorders.

Return to Driving After Hip and Knee Arthroscopic Procedures: A systematic review and meta-analysis

Background: Hip and knee arthroscopies are common orthopaedic procedures. As patients are looking to return to their regular schedules and regain their independence post-surgery, physicians often encounter the question of, “when can I drive again?” While safety of the patient is of the utmost importance when making these recommendations, it is equally important to consider the possibility of harm to others and potential legal ramifications. The purpose of this study is to consolidate evidence from available literature and undertake a systematic review and meta-analysis to determine when it is safe for patients to return to driving after hip and knee arthroscopic procedures. &#x0D; Methods: A systematic review was conducted using PRISMA guidelines. OVID, EMBASE, and COCHRANE databases were searched through June 2020 for articles containing keywords and/or MeSH terms “Hip arthroscopy” and “knee arthroscopy” in conjunction with “total brake response time” or “reaction time” in the context of automobile driving. Title review and full article review were done to assess quality and select relevant articles. Review Manager Version 5.4 was utilized for statistical analysis. &#x0D; Results: 8 papers were included in the meta-analysis of Brake Reaction Time (BRT). Meta-analysis of all Knee BRTs showed times slower-than or equal-to-baseline BRTs through 5 weeks, with a trend of improving BRT from 6 to 10 weeks (only weeks 8 and 10 were significant P &lt; 0.05). Of all Hip BRTs, week 2 showed slower-than-baseline BRTs, but after week 4 demonstrated a trend toward faster BRTs through week 8 (only week 8 was significant P &lt; 0.05). &#x0D; Conclusion: BRTs met baseline/control values and continued to improve after 6 weeks following knee arthroscopy and after 4 weeks following hip arthroscopy. Based on these results it would be safe to recommend return to driving at 6 weeks after knee arthroscopy and 4 weeks after hip arthroscopic procedures.

Resumption of Driving after Total Hip Arthroplasty: A Systematic Review and Meta-Analysis

Background/Objective: &#x0D; The advice given to patients on resumption of driving after total hip arthroplasty (THA) is inconsistent. Due to a lack of clear guidelines, surgeons make recommendations in the range of waiting 4 to 8 weeks after surgery to resume driving. Driving is a crucial part of daily life thus, withholding driving longer than necessary can have a detrimental social and economic impact on the patient. However, it is equally important to ensure that patients only resume driving once safe. This study presents a systematic review of the literature and a meta-analysis of simulation studies to establish when it is safe for patients to return to driving after hip arthroplasty. &#x0D; &#x0D; Methods: &#x0D; The review was performed according to the PRISMA guidelines. Medline, EMBASE, and CENTRAL databases were searched to June 2020 for studies examining ‘return to driving’ or ‘brake reaction time’ after ‘total hip arthroplasty’. Titles and abstracts were screened for inclusion, data was extracted, and studies were assessed for risk of bias. Review Manager, Version 5.4 was used for statistical analysis. &#x0D; &#x0D; Results: &#x0D; A total of 14 articles met the inclusion criteria. Of these, 7 measured brake reaction time and were included in the meta-analysis. The pooled means of both right and left THA show a brake reaction time (BRT) around or just above baseline at 1 week, 2 weeks and 3 weeks, and below baseline at 6 weeks, 12 weeks, 32 weeks and 52 weeks. Of these, the pooled means at 6, 32, and 52 weeks were significant (p &lt; 0.05). &#x0D; &#x0D; Conclusion: &#x0D; The mean recommended return to driving time was 4.5 weeks. Based upon the meta-analysis of BRT, it appears that it is safe to return to driving at 6 weeks post operatively. Orthopedic surgeons should use these results as a guideline when advising patients on when to resume driving.

Effect of warning message on driver’s stop/go decision and red-light-running behaviors under fog condition

The red-light-running (RLR) warning system has substantial potentials in helping drivers make proper stop/go decisions and reducing the RLR violations. Adverse foggy weather degrades drivers’ performances and may also affect the effectiveness of the RLR warning system. However, limited research has been conducted regarding the impact of the RLR warning on driving performances under foggy weather. Thus, this study aims to explore drivers’ decision-making process and RLR behaviors at intersection dilemma zones and evaluate the effectiveness of the RLR auditory-warning (RLR-AW) system in both fog and clear weather conditions. A concept of the RLR-AW system was proposed and designed in a driving simulator experiment. The simulated driving with the RLR-AW system was conducted in both clear and foggy weather conditions. The results show that drivers took compensation actions in fog while approaching the intersection, such as driving at lower speeds and using harder maximum brakes. The RLR-AW was able to reduce RLR rates in both clear and fog conditions, and drivers tended to respond more quickly and take smoother brake reactions with the RLR-AW provided. Moreover, the RLR-AW showed more remarkable influences on drivers’ behaviors in fog with higher decrement in brake reaction time and maximum deceleration rate. Overall, findings of the study shed light on the design of in-vehicle RLR-AW system and highlight the necessity of drivers applying the system in adverse weather conditions.

Analysis of car driver responses to avoid car-to-cyclist perpendicular collisions based on drive recorder data and driving simulator experiments

The reduction of cyclist injuries and fatalities is one of the important issues in traffic safety. To establish countermeasures to avoid collisions, it is necessary to understand driver’s responses in such critical situations. From videos of drive recorders, the behavior of cyclists and drivers that led to car-to-cyclist collisions can be analyzed objectively. In this research, the drivers’ responses to avoid car-to-cyclist perpendicular collisions were examined using videos of drive recorders, and through using a driving simulator.First, drivers’ responses to avoid collisions were compared between near-miss incidents and actual collisions using videos from drive recorders. In a statistical analysis of selected parameters of the drivers’ responses, the average values of different parameters such as the time-to-collision (TTC), the deceleration at the time the cyclist was first visible to the driver, and the braking reaction time (BRT) were significantly different between near-miss incidents and collisions. Applying logistic regression to the near-miss and collision data revealed that the BRT at the time the cyclist was first visible had the largest influence on collision occurrences. The velocity-TTC, and the velocity-distance graphs at the time of braking-onset was plotted; the car deceleration of 5.2 m/s2 was the threshold which discriminated near-miss and collisions.Second, the responses of people to avoid collisions against cyclists were investigated in a driving simulator. Based on real-world collision videos from the drive recorders, two scenarios were reconstructed where the crossing cyclist appeared suddenly from behind view-blocking obstructions at an intersection. Scenario A has a relatively large TTC of 1.9 s, and scenario B had a small TTC of 0.5 s. The BRT was significantly smaller in the group that avoided collisions than in the group that collisions occurred in scenario A, whereas all parameters (TTC, BRT, and car deceleration) were all significantly smaller in the group that avoided collision in scenario B.The driver response parameters (TTC, BRT and car deceleration) were comparable between the drive recorder data and the driving simulator experiments. It was demonstrated that the BRT is the most important parameter toward avoiding collisions. Some drivers who accelerated the cars at the intersections had large BRT, and this led to collisions. Additionally, it was observed that swerving of cars without braking was not effective for collision avoidance.

Time taken to resume driving following hip arthroscopy

BackgroundResuming driving is a common concern among patients undergoing hip arthroscopy. The present study aimed to assess whether patients who had undergone right hip arthroscopy presented with poorer driving performance than patients with normal hips and to analyze the time required to regain preoperative driving performance.MethodsForty-seven patients who had undergone right hip arthroscopy and consented to our test protocol were included in this study. Using an immersive driving simulator, the patients were tested for their brake reaction time (BRT), total brake time (TBT), and brake pedal depression (BPD) preoperatively and postoperatively. The first postoperative assessments were conducted when the patients could comfortably sit on the driving seat, and the follow-up assessments were conducted for 6 consecutive weeks at weekly intervals. The patients were divided into the following two groups based on the type of surgery that they underwent: the femoroacetabular impingement (FAI) surgery group and the simple hip arthroscopy (SA) group. Twenty healthy volunteers underwent driving assessments thrice at weekly intervals and constituted the control group. The braking parameters were compared between preoperative and postoperative measurements and among the FAI surgery, SA, and control groups.ResultsThe preoperative braking parameters of the patients who underwent arthroscopy did not differ significantly from those of the controls (p = 0.373, 0.763, and 0.447 for the BRT, TBT, and BPD, respectively). All braking parameters returned to normal in 2 weeks in the FAI surgery group and in 1 week in the SA group.ConclusionsOur study suggests that the driving performance of patients who underwent right hip arthroscopy is comparable to that of individuals with normal hips and that the braking parameters may normalize to the preoperative state at 1 week after SA and 2 weeks after FAI surgery.

Investigating the effect of blood alcohol concentration on motorcyclist’s riding performance using an advanced motorcycle simulator

It is largely accepted that drink-driving significantly increases the likelihood that a driver may engage in risk-taking behavior and thus road crash. Although there have been a few studies examining the effect of blood alcohol concentration (BAC) on rider performance in developed countries, there has not been any research on the effect of BAC levels on motorcycle rider’s performance in developing countries. This study is attempted to evaluate the effect of low BAC levels (i.e., ≤0.05 g/dL or 0.05) on riding performance of motorcycle riders in Vietnam using an advanced motorcycle riding simulator. Thirty-four motorcycle riders aged 18–40 complete simulated rides on three BAC levels, namely 0.00, 0.02, and 0.05. Riding performance indicators are measured and compared at different BAC levels. These indicators include average speed, average lateral overtaking distance, brake reaction time, acceleration, deceleration, and frequency of lane change. At the level BAC = 0.02 or lower, the negative effects on the rider’s ability to control a motorcycle safely are statically insignificant. At the level BAC = 0.05, all the performances are impaired and the negative effects become statistically significant. In comparison of between novice participants and experienced participants at the same level of BAC, mean speed and acceleration rates of novice participants are significantly higher than the experienced participant. Based on the findings, the paper further discusses empirical relationships between reduced riding performances and road crash risk, and insights into drink-riding deterrence policy-making with regard to motorcycle riders.

Reaction time and brake pedal force after total knee replacement: timeframe for return to car driving

PurposeThis prospective cohort study aimed to examine objective and subjective parameters in patients who underwent total knee replacement (TKR) to assess from when on driving a car can be deemed safe again.MethodsThirty patients (16 women, 14 men, age 66 ± 11 years) who received TKR of the right knee and 45 healthy controls (26 women, 19 men, age 32 ± 9 years) were asked to perform an emergency braking manoeuvre using a driving simulator. Brake pedal force (BPF), neuronal reaction time (NRT), brake reaction time (BRT), and subjective parameters (pain, subjective driving ability) were measured preoperatively as well as 5 days, 3–4, and 6 weeks after TKR.ResultsPreoperative NRT was 506 ± 162 ms, BRT 985 ± 356 ms, and BPF 614 ± 292 N. NRT increased to 561 ± 218 ms, BRT to 1091 ± 404 ms and BPF decreased to 411 ± 191 N 5 days after TKR. Three weeks after surgery, NRT was 581 ± 164 ms and BRT 1013 ± 260 ms, while BPF increased to 555 ± 200 N. Only BPF showed significant differences (p < 0.01). In week 6, all parameters were restored to baseline levels; patients showed significant pain decrease and evaluated their driving ability as “good” again.ConclusionBPF was the only parameter displaying a significant postoperative decrease. However, preoperative patients’ baseline levels and subjective confidence in driving ability were only reached 6 weeks after the operation. These results indicate that a minimum waiting period of 6 weeks should be considered before patients can safely participate in road traffic at their individual preoperative safety level again.Level of evidenceII.

Effect of total hip arthroplasty on brake reaction time and braking force.

The correct moment for return to driving after total hip arthroplasty (THA) remains unclear. Until today no uniform recommendation exists on the ability to perform an emergency brake.The aim of this prospective study was to investigate the braking ability of patients before and after THA implantation based on brake reaction time in milliseconds (BRT) and braking force in N (BF). In total, 25 patients (15 men, 10 women, mean age 51.3 ± 10.1 years) were treated with THA on the right side. Inclusion criteria consisted of a valid driving licence, frequent road participation and at least 2 years of driving experience. Exclusion criteria were underlying neurological disorders as well as severe complaints in the lumbar spine and the right knee joint. The brake ability was evaluated for emergency braking with a car simulator and a measuring sole. Measurements were performed preoperatively, 6 days, 2, 4 and 6 weeks after surgery. Preoperatively, the mean BRT was 671.3 ± 123.5 ms and the BF 455.4 ± 185.0 N. Significant differences were observed at 6 days and 2 weeks after surgery, (BRT 836.4 ± 219.7 ms, respectively, BRT 735.0 ± 186.7 ms, and BF 302.6 ± 154.9 N, respectively, BF 375.5 ± 149.3 N, p < 0.05). Only 4 weeks after, no significant differences were seen compared to pre-operative with a BRT of 647.0 ± 91.9ms (p = 0.354) and BF of 435.9 ± 177.4 (p = 0.843). Furthermore, the BRT improved significantly after 6 weeks (607.4 ± 87.6; p = 0.005). The braking force is significantly reduced, and the brake reaction time is prolonged directly after surgery for at least 2 weeks. After 4 weeks, no statistically significant differences were measured, although special care should still be taken during return to activity.

Understanding take-over performance of high crash risk drivers during conditionally automated driving

Understanding driver behavior of conditionally automated driving is necessary to ensure a safe transition from automated to manual driving. This study aimed to examine the difference in take-over performance between high crash risk (HCR) and lower crash risk (LCR) drivers in emergency take-over situations during conditionally automated driving. In the current simulator study, a 3 × 3 (within-subjects) factorial design was used, including the task factors (no task, reading the news, and watching a video) and time budget factors (time budget = 3 s, 4 s, and 5 s). Forty-eight participants completed a test drive on an approximately 10 km long two-way six-lane urban road. The participants firstly were in manual control and then switched to the automated driving mode at a speed of 50 km/h. The automated driving system was able to detect a broken car in the ego-lane and requested the driver to take over the control of the vehicle. There are at least one or two other vehicles or motorcycles on each side of the ego-vehicle, resulting in fewer escape paths. For the two non-handheld non-driving-related tasks (NDRTs), the participants were asked to be fully engaged in a task without any need to monitor the road environments. Each participant completed nine emergency take-over situations. The participants were classified into two groups that were labeled LCR (N ≤ 2) and HCR drivers (N ≥ 3) according to the number of accidents per driver. The results show that LCR drivers had shorter brake reaction time compared to HCR drivers. For all drivers, the engagement in a task led to longer response times, and the time budget affected the longitudinal vehicle control. In addition, the task affected the response times for LCR and HCR drivers, but only the time budget affected the longitudinal vehicle control for LCR drivers. For all drivers, LCR and HCR drivers, the time budget and task affected the safety of take-over. Especially, the two non-handheld everyday tasks seem to have a similar effect on the drivers’ workload. Therefore, the HCR drivers had a lower hazard perception compared to the LCR drivers, and the factor regarding the individual difference of driving ability in take-over situations should be considered to design safe take-over concepts for automated vehicles.

Cardiorespiratory fitness and sex assigned at birth contribute to brake reaction time in older adults

IntroductionAge-related increases in reaction time (RT) are pervasive. Driver RT is a crucial component of roadway safety. Superior cardiorespiratory fitness (CRF) is associated with faster RTs on a variety of behavioral tasks. Driver RT, as with any RT measure, is comprised of constituent components that contribute to a total response time (TT). Simple RT (sRT) is comprised of the requisite sensory and central processing of TT. Movement time (MT) is comprised of the requisite movement of a particular behavioral response (e.g., moving your foot from the accelerator to the brake pedal). This study aimed to determine the strongest predictor of constituent components of driver RT on a brake onset test. MethodsCross-sectional analysis. Predictor variables included CRF, age and sex. Participants were 50 community-dwelling older adults between the ages of 60 and 77 (mean age = 66.5 years, SD = 4.1). Maximal graded exercise tests were used to assess CRF. A driving simulator was used to assess constituent components of driving-related RT. Results: Findings indicated that CRF was the largest contributor to sRT variance (beta = −0.35, p = 0.03). Sex was the largest contributor to MT (beta = −0.44, p = 0.003) and TT (beta = −0.28, 0.05) variance.CRF also demonstrated a marginal contribution to TT variance (beta = −0.25, p = 0.08). Age did not significantly contribute to sRT, MT or TT. ConclusionsAge-related increases in RT can jeopardize roadway safety. Findings from this study demonstrate that a modifiable lifestyle variable may have the ability to reduce roadway risk by improving constituent components of driver RT.

Return to Driving After Foot and Ankle Surgery: A Novel Survey to Predict Passing Brake Reaction Time.

Introduction. Brake reaction time (BRT) is an accepted method for establishing recommendations for safe return to driving by the National Highway Traffic Safety Administration. Other than performing a BRT test in clinic, there is no established clinical tool to help physicians differentiate safe from unsafe drivers once patients reach general recovery milestones. The purpose is to present individual recommendations to the patient through a novel, validated survey evaluating safe return to driving after orthopaedic surgery of the right foot and ankle. Methods. A total of 171 patients undergoing 1 of 3 specific foot and ankle procedures were prospectively enrolled. A 4-question survey and BRT were completed 6 weeks postoperatively. The following questions were asked: (1) "I think my brake reaction time is slower than most drivers my age," (2) "I think my brake reaction time is faster than most drivers my age," (3) "I think my brake reaction time is about the same as most drivers my age," (4) "Based on what I think my brake reaction time is, I think I am ready to drive." Internal consistency was determined with Cronbach's α and item total correlation. External validity was determined by Spearman's correlation coefficient. A BRT less than 0.850 s was considered as a pass. Results. Of 171 patients, 162 (95%) with ages ranging from 21 to 83 years achieved a passing BRT by 7.6 weeks. After removing 1 question because of internal inconsistency, the optimal threshold for predicting passing BRT was 10/15 points or higher, which had 99% probability of success that a patient would pass the BRT (95% CI = 96%, 100%). Conclusion. This novel, 3-question driving readiness survey can accurately predict a passing BRT Achilles rupture repair, total ankle arthroplasty, and hallux valgus correction performed in the right foot and ankle as early as 6 weeks postoperatively.Level of Evidence: Level II: Comparative study.