Deceleration Lane Research Articles

Capacity analysis of short-distance continuous diversion areas on mountainous urban expressways.

The short-distance continuous diversion area plays a crucial role within mountainous urban expressway systems, significantly enhancing the efficiency of specialized road sections through capacity analysis. This study develops a capacity calculation model tailored to the diversion area's unique characteristics and principal capacity-influencing factors. Initially, the research focuses on a specific short-distance continuous diversion area of a mountainous urban expressway, employing video trajectory tracking technology to gather trajectory data. This data serves as the basis for analyzing road and traffic characteristics. Subsequently, the model computes the capacity influenced by eight variables, including diversion point spacing and deceleration lane length, using VISSIM simulation experiments. A gray correlation analysis identifies key factors, which guide the establishment of the model's fundamental structure through two-factor surface fitting results. Mathematical statistical methods are then applied to resolve the model's parameters, culminating in a robust capacity calculation model. The findings reveal that diversion point spacing, along with primary and secondary diversion ratios, significantly influence capacity. Notably, the capacity exhibits a marked quadratic polynomial relationship with the primary diversion ratio and diversion point spacing, and a linear relationship with the secondary diversion ratio. The model's validity is confirmed through a case study at the diversion area north of Huacun Interchange in Chongqing Municipality, where the discrepancy between calculated and actual capacities is under 5%, underscoring the model's high accuracy. These results offer valuable theoretical and methodological support for the planning, design, and traffic management of diversion areas.

Analysis of the Duration of Mandatory Lane Changes for Heavy-Duty Trucks at Interchanges

Due to the different driving characteristics of different vehicle models, inappropriate mandatory lane changes (MLCs) by heavy vehicles at interchanges often lead to serious traffic accidents. Therefore, this paper focuses on the impact of road geometric design on the MLC duration of heavy trucks by using full time-domain trajectory data. Specifically, we use the generalized additive time-varying Cox model to establish the MLC duration model of heavy trucks at interchanges, then analyze the combined influence of geometric elements. The results show that the consistency index of the model is 0.9, indicating that it has advantages in building models in complex environments. The length of the deceleration lane, ramp type, and curve radius have a significant impact on the validity and duration of MLCs. This finding provides a theoretical and methodological reference for the safety analysis of interchange areas and the refinement of road geometric design.

Purpose of acceleration and deceleration lanes. Comparison of the regulatory framework for the design acceleration and deceleration lanes in Bulgaria, Austria, Germany and the USA (California).

The report examines and analyzes the purpose of acceleration and deceleration lanes at two-level road interchanges. For the preparation of the current report are used the regulatory framework for the design of acceleration and deceleration lanes from Bulgaria, Austria, Germany and USA – California. The design elements of the acceleration and deceleration lanes are compared in detail. Widths and lengths of lanes, merging zones, angles and slopes. The conclusions of the report are given as guidelines for good practice in the design of road interchanges at one and two levels.

Calculation of Dangerous Driving Index for Two-Wheeled Vehicles Using the Analytic Hierarchy Process

Given the high incidence of traffic accidents and fatalities on two-wheeled vehicles, there is a growing need for safety management. However, studies on evaluating two-wheeled vehicle driving in a quantitative and comprehensive form are insufficient. In this study, 11 items were defined for the first step to evaluate two-wheeled vehicle driving: signal violation, central line violation, helmet violation, pedestrian close driving, sidewalk driving, reverse lane driving, speed violation, rapid acceleration, rapid deceleration, rapid turn, and rapid lane change. The items were classified into three categories (traffic violation, pedestrian threat, and reckless driving), and their weights were derived using the AHP technique. For rapid acceleration, rapid deceleration, rapid turn, and rapid lane change, a high-performance driving simulator was used to establish risk criteria and calculate the weight based on the degree of risk. The calculated weight of each item indicates its importance in evaluating two-wheeled vehicle driving, with helmet violation (0.158), speed violation (0.124), and pedestrian close driving (0.122) having the highest weights. Finally, the dangerous driving index for two-wheeled vehicles was calculated by the weights of each evaluation item and applied to the driving trajectory data.

Calculation Method of Deceleration Lane Length and Slope Based on Reliability Theory

The deceleration lane is an important part of the freeway, and the rationality of its design parameters affects the exit accident rate. The traditional calculation method is based on the design of speed and vehicle parameters using deterministic methods, ignoring the randomness of the driver’s deceleration behavior. It is necessary to calculate the length and slope of the deceleration lane in detail according to the deceleration characteristics of the driver in the deceleration section by using the uncertainty method. This paper describes a study on the maximum longitudinal slope of the downhill section of the deceleration lane, where the safety of diverging vehicles is unfavorable. By collecting deceleration lane data from interchanges around Xi’an (Shaanxi Province, China, Coordinates: 108.95, 34.27) and analyzing the deceleration characteristics of vehicles, we propose a new deceleration model. In addition, the limit-state functions of the length and slope of the deceleration lane have been established based on the reliability theory. Finally, according to the deceleration characteristics, we determined the probability distribution of key parameters in the vehicle deceleration process. We used the Monte Carlo Simulation (MCS) and the Improved First-Order Second Moments (IFOSM) calculation model to calculate the length and slope of the deceleration lane, respectively. Finally, we propose the recommended values for the length and slope of the deceleration lane. The results of the study showed that: (1) The movement process of the vehicle on the deceleration section adopts a uniform deceleration, and the truck and the car start to decelerate from the starting of the taper section and diverging point, respectively. (2) The control vehicle in the deceleration lane calculation model is the compact car. (3) The reliability theory has good applicability in calculating freeway alignment indexes. It fully considers the probability of driver deceleration behavior in the calculation model, which provides a more suitable method for the calculation of deceleration lane indexes.

Predicting safety performance on motorways during the pandemic based on geometric design: A case study in Portugal

The mobility restrictions due to the covid-19 pandemic have created an unprecedented situation in the road system. Declared lockdowns have significantly altered the traffic volumes and perhaps also driver behavior. This study conducts research on crashes occurred on motorway A29 in Portugal before and during the disrupted mobility context. Safety performance functions were adjusted with negative binomial distribution. The segmentation was based on horizontal alignments. 5 of the 27 variables initially considered were found to be significant; namely traffic volume, segment length, curvature change rate, presence of deceleration lane and year. The quality of the fitted models was verified using cumulative residuals plots. The results showed that a traditional statistical modelling approach explains accident occurrence in a similar way before and during the pandemic.

СТРАТЕГИЯ ПРОЕКТИРОВАНИЯ СЪЕЗДОВ ТРАНСПОРТНЫХ РАЗВЯЗОК В УСЛОВИЯХ ПЛОТНОЙ ГОРОДСКОЙ ЗАСТРОЙКИ

The relevance of the research is defined by necessity to find a way of designing transport interchanges in densely built-up urban areas in the conditions of the constantly growing volume of traffic on urban highways. Current Russian regulations in road design industry significantly limit the minimum values of ramp design speed and as a consequence the minimum values of curve radii for loop ramp on transport interchanges. Setting of such values lead to abandon the number of ramps and to add some traffic lights. In this research, local and foreign regulations and scholarly articles are studied and an-alyzed. The required calculations of minimum values of curve radii for loop ramp and the values of curve widening are also performed. The main result of research is preliminary conclusions of the pos-sibility to decrease the minimum value of ramp design speed, subject to certain conditions. The strate-gy for changing limit values on transport interchanges is created in consideration of multifaceted ap-proach with the revaluation of the side friction factors, length of acceleration and deceleration lanes and a number of other parameters to ensure the road safety in densely built-up urban areas.

Acceleration and Deceleration Rates in Interrupted Flow Based on Empirical Digital Tachograph Data

The acceleration and deceleration rates are crucial road design reference values in terms of traffic safety. The purpose of acceleration and deceleration lanes is to reduce the speed difference between the mainline and ramp to minimize rear-end collision. Thus, in traffic safety and traffic flow operational aspects, the acceleration and deceleration lane lengths need to be long. Moreover, excessively long minimum acceleration or deceleration lane length regulations may cause hesitancy to connect new facilities with the road. Despite their relevance, acceleration and deceleration rates have not been updated for many decades. In this study, we analyze the digital tachograph data of vehicles stopped at signalized intersections at red lights and empirically deduce the acceleration and deceleration rates that reflect recent vehicle performance and driver behavior. Finally, we suggest a new corner clearance distance to safely connect the new road near a signalized intersection in urban and rural areas derived from our empirical acceleration and deceleration rates.

Safety Evaluation of Freeway Exit Ramps with Advisory Speed Reductions

Posted speed limits inform drivers of the legal maximum allowable speed. In contrast, advisory speeds provide recommendations to drivers based on highway design, operating characteristics, and conditions. Various studies have investigated the safety impacts of speed limit changes, particularly on high-speed rural highways. One area of particular concern on such roadways is the approach to exit ramps that require substantive speed reductions, such as loop ramps. To date, there has been limited research examining the safety impact of the differential between the mainline speed limit and the lower exit ramp advisory speeds. This study aims to evaluate this relationship through the estimate of a series of safety performance functions. Random effects negative binomial regression models were estimated using data from 187 exit ramps where advisory speed signs are present throughout Michigan. The analyses were conducted based on a five-year period from 2014 to 2019, excluding 2017 data because of speed limit increases. In addition to speed differentials, various roadway characteristics such as deceleration lane length and curve radius were also evaluated. Results indicate that crashes increased as the difference between mainline and ramp speed increased. Crashes were also shown to decrease on ramps where the upstream deceleration lane length was greater than the minimum recommendation as per current design guidance.

The Compatibility between the Takeover Process in Conditional Automated Driving and the Current Geometric Design of the Deceleration Lane in Highway

In recent years, the takeover process of conditional automated driving has attached a great deal of attention. However, most of the existing research has focused on the effects of human-machine interactions or driver-related features (e.g., non-driving-related tasks), while there is little knowledge about the compatibility between the takeover process and existing road geometric design. As there is a high possibility that drivers must take over the vehicle before they diverge from the mainline of the highway, this explanatory study aimed to examine the compatibility between the takeover process and the current deceleration lane geometric design. The distribution range of existing deceleration lanes’ lengths were obtained through a geo-based survey. Nine scenarios were recreated in the driving simulator which were designed with various deceleration lane lengths and driving modes (different takeover time budgets and manual driving as the baseline group). A total of 31 participants were recruited to take part in the experiment, their gaze behaviors were recorded simultaneously. Results showed that, compared with manual driving, both drivers’ horizontal and vertical gaze dispersion increased, while drivers adopted higher deceleration in the mainline and merged into the deceleration lane later under takeover conditions. Moreover, a longer deceleration lane could benefit vehicle control. However, its marginal effect was reduced with the increase of deceleration lane length. These findings can help automated vehicle manufacturers design dedicated takeover schemes for different deceleration lane lengths.

Highway Deceleration Lane Safety: Effects of Real-Time Coaching Programs on Driving Behavior

Real-time coaching programs are designed to give feedback on driving behavior to usage-based motor insurance users; they are often general purpose programs that aim to promote smooth driving. Here, we investigated the effect of different on-board real-time coaching programs on the driving behavior on highway deceleration lanes with a driving simulator experiment. The experiment was organized into two trials. The first was a baseline trial, in which participants drove without receiving any feedback; a cluster analysis was then performed to divide participants into two groups, based on their observed driving style. One month later, a second trial was carried out, with participants driving on the same path as the first trial, this time receiving contingent feedback related to their braking/acceleration behavior. Four feedback systems were tested; overall, there were eight experimental groups, depending on the clustered driving style (aggressive and defensive), feedback modality (visual and auditory), and feedback valence (positive and negative). Speed, deceleration, trajectory, and lateral control variables, collected before and onto the deceleration lane, were investigated with mixed ANOVAs, which showed that the real-time coaching programs significantly reduced speeds and maximum deceleration values, while improving lateral control. A change toward a safer exit strategy (i.e., entering the lane before starting to decelerate) was also observed in defensive drivers.

Crash- and Simulation-Based Safety Performance Evaluation of Freeway Rest Area

The main objective of this study was to evaluate the safety effects caused by altering the lengths of deceleration and acceleration lanes at rest areas on expressways in Korea. Although general conclusions can be found through crash-based safety analysis, to examine more specific optimal conditions considering various traffic conditions, this study proposes a novel framework to explore and evaluate crash-based and simulation-based safety performances. For this purpose, the safety performance function (SPF) and crash modification factor (CMF) were developed to reflect real-world safety impacts. To consider nonlinear trends of the parameters, nonlinearizing link functions were introduced into the analysis. Two types of simulation analyses were conducted to (1) find the combination of surrogate safety measures (SSMs) that best fit with the crash-based safety performance results and (2) determine the optimal lengths of deceleration lane and acceleration lanes for different traffic conditions. The results showed that the best length of deceleration lane of a rest area is between 240 and 260 m, depending on the traffic conditions. The results also indicated that the optimal length of acceleration lane of a rest area is between 385 and 400 m, depending on the traffic parameters. The findings of this study could be used to determine the safety solutions with a micro-traffic simulator.

Aging drivers and post delineated express lanes: Threading the needle at 70 miles per hour

Post-delineated express lanes represent a combination of driving complexities that are particularly difficult for older drivers to navigate. The narrow geometry and high speeds that are common to this treatment reflect a critical test for drivers whose depth perception, contrast sensitivity, and visual processing speed are reduced. The present study was designed to empirically examine the effects of age and color of express lane delineators on driver behavior. Three groups of participants (aged 18–39, 40–64, and 65 + years old) were required to complete a series of simulated driving scenarios consisting of combinations of single and dual lane configurations, with speed and lane position measured at the beginning and midpoint of each express lane. All drivers were pre-screened on various visual functioning abilities. Drivers in the 65 and older group show significant age-related declines in depth perception, contrast sensitivity, and phoria which were subsequently correlated with a wide range of driving measures including deceleration rate, brake time, jerk, speed, and lane position. Age related perceptual declines were statistically correlated with slower driving speed and wider lane deviations, including a statistically significant increase in the number of excursions beyond the typical 12-foot lane width. Based on these findings, the behavior of senior drivers was identified as a distinct design condition that should govern the design of high-speed, narrow geometric conditions. This age group requires wider lane widths, particularly at the beginning of single-lane post delimited sections, wider buffer areas around the post markers, and dual lane configurations wherever possible.

Optimal design alternatives of advance guide signs of closely spaced exit ramps on urban expressways

Advance guide signs for exit ramps along urban expressways are increasingly critical, enhancing safety and mobility by improving the flow of vehicles exiting urban expressways. However, research has devoted scant attention to advance guide signs for exit ramps. This study aimed to identify and propose optimal design alternatives for exit ramp advance guide signs for different types of exit spacing. This study conducted a driving simulation experiment consisting of five design alternatives of advance guide signs and two exit ramp spacing variation. Eight indicators were measured. The repeated-measure analysis of variances (ANOVA) and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) were performed for the influence analysis and efficiency evaluation of different schemes. Influence analysis results showed better design alternatives in five schemes of advance guide signs, enabling drivers to more easily locate destination exits and change lanes fewer times, in addition to reducing drivers’ need to decelerate, and improving traffic flow in the key influence range of destination exit ramps. The percentage of drivers successfully locating the destination exits also increased with optimal design alternatives of advance guide signs. When the exit ramp spacing tightened, on the other hand, drivers had to make more lane changes and accelerate and decelerate more frequently in the key influence range. As a result, a lower percentage of drivers successfully located destination exits. Efficiency evaluation results were also obtained. In tight spacing, three advance guide signs are recommended to be placed at 1 km, 0.5 km and 0 km prior to the beginning of the tapered deceleration lane. If conditions are limited, at least two advance guide signs should be used. With greater spacing, four advance guide signs are recommended, located at 2 km, 1 km, 0.5 km, and 0 km prior to the beginning of the tapered deceleration lane. If road conditions are limited, three advance guide signs should be used.

Analysis of the effects of lead-vehicles on drivers approaching deceleration lanes on a dual carriageway road

The presence of other vehicles interferes with the recognition of the key features of the road environment and induces drivers to concentrate their attention on the moving source of information, reducing the attention towards the fixed elements of the road. In presence of lead-vehicles, drivers focus first on the moving objects and unconsciously slow the search of information for guidance and control. The stimulus-driven attention tends to prevail on the goal-directed attention (Kock, 2004) and the space perception is altered. The aim of this study is to understand how the improper lookout caused by the presence of moving objects like lead-vehicles affects the manoeuvres of drivers navigating interchanges, in proximity to (unexpected) visual elements of the road platform as deceleration lanes. In order to measure the effects of the moving vehicles in the visual scene, a group of twelve drivers preformed driving tests under different conditions in correspondence to the exit lanes of two different interchanges located on a dual carriageway rural road. Their performances were tracked, recorded and analysed by electronic devices and digital cameras installed on the test-car. The results illustrate the drivers’ reaction in presence of lead vehicles located in the centre of their visual field and show how the diverging manoeuvres and the perception of the road environment are influenced.

Research on deceleration lane length of special ramp for freight cars on passenger-freight separation expressway

In order to obtain the truck-specific ramp deceleration lane length index for passenger and cargo separation, the UMRR chain Kepler radar speedometer is used to collect the vehicle speed data under the free-flow state of the ramp feature points (starting point, diversion point and small nose point of the transition section). The KS normal distribution test is carried out on the sample data. On the basis of satisfying the test requirements, the speed and acceleration characteristics of the deceleration lane vehicle are analysed, and then the parameters in the secondary deceleration theory are re-determined. Based on this, the deceleration lane length value of the truck-specific ramp is calculated.

Impacts of experimental advisory exit speed sign on traffic speeds for freeway exit ramp.

Many crashes occur around freeway exit ramp areas in China due to excessive speeds and large speed variances. Traditionally, a single posted ramp speed limit sign is installed around the physical gore area to manage the speed. To address this issue, the study presented in this paper proposes the use of an advisory exit speed sign (AESS), which is an additional exit speed limit sign positioned along the deceleration lane to accommodate the speed changes ahead of the physical gore. The study selected three sites with similar exit ramp configurations and two scenarios (with AESS/without AESS) to quantify the influences of the AESS on the speed of exiting vehicles. The speed profiles of 480 vehicles were obtained based on 12 hours of data collection. A t-test was applied to verify the reduction in mean speed between the two scenarios. The results show that the AESS in this study was effective in reducing the mean speed and 85th percentile speed, especially in the taper and deceleration lane. It was clearly seen that drivers began to decelerate in advance when the AESS was installed, which led to a smooth deceleration process, especially on the segment between the theoretical gore and the physical gore. The AESS was also helpful in reducing speeding to some extent. Although the effects of the AESS on speed reduction at curved ramps were not ideal, the speed fluctuation range tended to be more contracted when the AESS was installed. This paper provides useful information for researchers, managers, and engineers when considering the implementation of AESS.

Optimization Design of Expressway Entrance and Exit Based on Actual Traffic Flow Characteristics

The combination area of entrance and exit is the frequent bottleneck of urban expressway system. The running state of traffic flow in combination area is closely related to the key parameters including the acceleration and deceleration lane length, the interweaving area length, the sign identification, etc. And the analysis of traffic flow status can in turn guide the design of road engineering. Therefore, this paper proposes the geometric elements optimization model and design results of the expressway entrance and exit combination area based on the actual traffic flow characteristics and driver’s driving characteristics. To verify the superiority of the optimization model, this paper takes a combination area of Jinzhai Expressway in Hefei City as an example, and after a large number of road traffic surveys, uses VISSIM to simulate and evaluate optimization effect based on proposed model and calculation results. The results show that the optimization model based on traffic flow characteristics is better at improving traffic flow status, especially during the peak period, the average delay of the research section decreased by 18.1%, and the average pass rate of the bottleneck increased by 13.6%.

Vibration Effect Produced by Raised Pavement Markers on the Exit Ramp of an Expressway

Driving over raised pavement markers (RPMs) spaced at different spacing, the human body will experience different vibrations. To explore whether RPMs situated at the exit ramp of an expressway induce a good vibration warning effect, this paper determines the spacing of RPMs situated along a deceleration lane and curved ramp. Models of roads, vehicles, and RPMs are first established in the ADAMS software, after which an integrated human-chair model constructed in SolidWorks is imported into ADAMS, and then the complete model is formed so that vibration simulations of different types of vehicle at different spacing and speeds can be carried out. The results show that the vibration warning effects of the spacing proposed by the existing Chinese specifications and this paper are basically between level III and level IV, the driver’s subjective feeling is between less comfortable and uncomfortable, and both induce a good vibration warning effect. For a linear deceleration lane, when considering traffic safety, a spacing of 3 m is recommended; when considering the economy, a spacing of 6 m is recommended. For a curved deceleration lane and curved ramp, according to the actual curve radius, the spacing of RPMs can refer to the spacing recommended in the paper. In addition, the vibration warning effect for cars and semi-trailer trucks initially increases with an increase in the speed; then, after reaching a certain peak speed, the effect decreases with an increase in the speed, and finally, it tends to become gentle at speeds exceeding 100 km/h. The vibration warning effect for a semi-trailer truck is better than that for a car under the same spacing and speed.

Estimating Acceleration and Deceleration Lane Lengths by Analyzing Vehicle Speed Variation of Rest Areas for Drowsy Drivers

Estimating Acceleration and Deceleration Lane Lengths by Analyzing Vehicle Speed Variation of Rest Areas for Drowsy Drivers