Low-speed Roads Research Articles

The role of posted speed limit on pedestrian and bicycle injury severities: An investigation into systematic and unobserved heterogeneities

The posted speed limit, as a proxy of actual speed, is one of the most fundamental predictors of active travelers’ (pedestrian and bicyclist) injury outcomes when involved in crashes with motor vehicles. Although earlier studies predominantly considered posted speed limit as an exogenous variable and provided highly insightful findings, majorities of them assume the effects of active traveler behavior to remain the same across different posted speed limits, which in turn neglect the heterogeneity in active traveler behaviors on high-speed roads vs. low-speed roads. This study proposes to develop a latent segmentation-based active traveler injury severity model to relax the homogeneity assumption of the posted speed limit by active traveler behavior. Specifically, this study proposes to estimate a latent segmentation-based correlated random parameters generalized ordered logit model to examine active travel injury severity mechanisms. The proposed model accommodates systematic heterogeneity in the effects of posted speed limit, crash year and active traveler group by using a piecewise linear function in injury severity component of the latent segment model. The model is demonstrated by using active traveler crash data from Queensland, Australia, for the years 2015 through 2019. To demonstrate the implications of the estimated models, a number of hypothetical scenario analyses are performed with a specific focus on active traveler behavior and reduction in posted speed limits. The outcomes from the hypothetical scenario analysis highlighted that a 76 % (73 %) reduction in active traveler fatalities can be achieved by converting 50–60 km/hr roadways to 10–40 km/hr roadways in the urban areas (rural areas) of Queensland. The outcomes of the study will allow us to identify effective speed management strategies while targeting those with high-risk behavior.

Total Mineral Content in Raw Materials of Ten Medicinal Plants from Roadside Biotopes of Voronezh Oblast.

The total mineral content was studied in medicinal plants from roadside and railside biotopes of the Voronezh region. Pharmacopoeial plant raw materials of 10 species were evaluated: roots of Taraxacum officinale F.H. Wigg and Arctium lappa L.; herb of Polygonum aviculare L., Artemisia absinthium L., Leonurus quinquelobatus Gilib., and Achillea millefolium L.; leaves of Urtica dioica L. and Plantago major L.; and flowers of Tanacetum vulgare L. and Tilia cordata Mill. Plant raw materials were collected near roads and railways of various types in the periods specified in regulatory documents. The total ash content in plant material was used to determine the minimum allowable distances from various roads and railways for collecting plant material. The minimum allowable distance from heavy-traffic motorways was recommended to be 210 m in the forest zone, 240 m in the forest-steppe zone, and 380 m in the steppe zone. A distance of at least 80 m was recommended for secondary low-speed roads and railways.

Examination of the Factors Influencing the Electric Vehicle Accident Size in Norway (2020–2021)

With the great increase of electric vehicles (EVs) in the past decade, EV-involved traffic accidents have also been increasing quickly in many countries, bringing many new traffic safety challenges. Norway has the largest EV penetration rate in the world. Using the EV accident data from Norway in 2020 and 2021, this study aims to investigate the features of EV safety comprehensively. Firstly, a descriptive analysis is conducted. It has been found that rear-end collisions are the major collision type of EVs, and EVs are very likely to collide with pedestrians/cyclists. In addition, in terms of roadway type, EV accidents mainly occur on medium- and low-speed roads; in terms of environment, they mainly occur in good visibility conditions and dry road surface conditions. Then, a regression analysis is conducted to identify the key factors affecting the accident size, which is the number of traffic units involved in an accident and taken as the accident severity surrogate here. Since EV accidents are divided into four categories in order of accident size, the ordered logit model is adopted. It divides a multi-categorical dependent variable into multiple binary data points in order and calculates the probability of the dependent variable falling into each category with the logit model, respectively. The estimation results indicate that time of day, speed limit, and presence of medians have statistically significant impacts on the EV accident size. Finally, some countermeasures to prevent EV accidents are proposed based on the research results.

The Surface Accelerations Reference—A Large-Scale, Interactive Catalog of Passenger Vehicle Accelerations

There is a need for a large-scale, real world, diverse, and context rich vehicle acceleration catalog that can be used to design, analyze, and compare various intelligent transportation systems. This paper fulfills three primary objectives. First, it provides such a catalog through the Surface Accelerations Reference, which is openly available as an interactive analytics tool as well as an open and downloadable dataset. The Surface Accelerations Reference statistically describes the driving profiles of about 3,500 individuals contributing 34 million miles of continuous driving data collected in the Second Strategic Highway Research Program Naturalistic Driving Study (SHRP 2 NDS). These profiles were created by summarizing billions of longitudinal and lateral acceleration epochs experienced by the participants. Second, this paper introduces a standardized methodology for creating such a catalog so that similar acceleration profiles can be produced for other human cohorts or automated driving systems. Finally, the data are used to analyze the effect of roadway speed category on the rates of lateral and longitudinal acceleration epochs at various thresholds. It is observed that, for the median driver, the rates of epochs are up to three orders of magnitude higher on low-speed roads as compared to high-speed roads. This catalog will facilitate intelligent vehicle system designers to compare and tune their systems for safer driving experiences. It will also allow agencies with similar data to create comparable catalogs facilitating safety and behavioral comparisons between populations.

Optimal Routing and Charging of Electric Logistics VehiclesBased on Long-Distance Transportation and Dynamic Transportation System

The application of electric vehicles (EVs) in the logistics industry has become more extensive. However, the mileage limitation of electric logistics vehicles (ELVs) and the long-distance distribution of ELVs have become urgent problems. Therefore, this paper proposes a long-distance distribution model for ELVs based on dynamic traffic information considering fleet mileage, distribution time and total distribution cost as the optimisation objectives, thus reasonably planning road selection and charging, and alleviating “mileage anxiety” in the long-distance distribution of ELVs. The model proposed in this paper comprehensively considers the characteristics of the high-speed and low-speed roads, the changes in road traffic flow on weekdays and non-weekdays, the time-of-use electricity price of electric vehicle charging stations (EVCSs) and uses the M/M/s queuing theory model to determine the charging waiting time. Finally, a real traffic network is taken as an example to verify the practicability and effectiveness of this model.

Effects on crash risk of automatic emergency braking systems for pedestrians and bicyclists

Objective The first automatic emergency braking (AEB) system was presented in 2003 and aimed to mitigate or reduce rear-end crashes. Since then, several AEB systems aimed to reduce other collision types have been introduced and studies have shown that they reduce crash risks. The aim with this study was to evaluate crash reductions of cars fitted with AEB systems with pedestrian detection and those with bicyclist detection. Methods The study is based on the Swedish Traffic Accident Data Acquisition that includes road traffic accidents reported by the police and by emergency hospitals. Crashes occurring between 2015 and 2020 and with cars from model years 2015 to 2020 were included. The statistical analysis used odds ratio calculations with an induced exposure approach where the outcomes of sensitive and nonsensitive crashes were studied. The sensitive crashes were hit pedestrians and bicyclists, respectively. The nonsensitive crash type in both comparisons was struck vehicles in rear-end crashes. Evaluations were also made for different light and weather conditions and for high and low speed roads. Results Seven hundred and twelve hit pedestrians and 1,105 hit bicyclists were included, and the nonsensitive crashes consisted of 1,978 vehicles. The overall reduction on crash risk for AEB with pedestrian detection was 8% (±15%; ns) and for AEB with bicyclist detection it was 21% (±17%). When separating for light conditions, no reduction in crash risk for AEB with pedestrian detection nor for AEB with bicyclist detection could be seen in darkness. However, in daylight and twilight conditions, AEB with pedestrian detection reduced pedestrian crash risk by 18% (±19%; ns) and AEB with bicyclist detection reduced bicyclist crash risk by 23% (±19%). No significant reductions could be seen when separating for weather conditions except for a 53% (±31%) reduction for bicyclists in rain, fog, and snowfall. A larger reduction on high-speed roads (50–120 km/h) compared with low-speed roads (10–40 km/h) was also found. Conclusions AEB systems with bicyclist detection were found to reduce the numbers of hit bicyclists, especially in daylight and twilight conditions. In darkness, no reduction for hit pedestrians or bicyclists was found.

Assessment of Total Mineral Content in Raw Materials of Ten Medicinal Plants from Roadside Biotopes (Voronezh Region)

Abstract—The total mineral content in medicinal plants from the roadside and railside coenoses of the Voronezh region was studied. The pharmacopoeial plant raw materials of 10 species were evaluated: roots of Taraxacum officinale F.H. Wigg and Arctium lappa L.; herb of Polygonum aviculare L., Artemisia absinthium L., Leonurus quinquelobatus Gilib., and Achillea millefolium L.; leaves of Urtica dioica L. and Plantago major L.; flowers of Tanacetum vulgare L. and Tilia cordata Mill. For collecting medicinal plant raw materials, the minimum allowable distances from different types of roads and railways were determined based on the total ash content indicator. For different natural zones, the minimum allowable distance from the heavy traffic motorways is: forest zone – 210 m, forest–steppe zone – 240 m, and steppe zone (devoid of tree and shrub vegetation) – 380 m. For secondary low-speed roads and railways, the minimum recommended distance is 80 m.

Sensitivity of Input Parameter on CNOSSOS-EU Road Emission Levels

The United Kingdom Department for Food and Rural Affairs (Defra) commissioned a series of studies investigating the sensitivity of the CNOSSOS-EU noise assessment method. CNOSSOS-EU presents challenges in terms of input data accuracy and availability. For this reason, the studies were commissioned to support data decision making and quantify potential uncertainty in Defra's national noise model. The quality framework set out in Directive 996/2014 requires uncertainty in road emission levels at source to correspond to an uncertainty of ±2dB(A). By calculating emissions across a range of values for input parameter within various scenarios in which all other parameters were kept constant, changes in road traffic noise emissions were observed. This was performed separately for each of the five CNOSSOS-EU vehicle categories as well as for a selection of hypothetical composite road traffic flows. A similar analysis was then performed for a series of road surface types. The results were used to indicate which input parameters road traffic noise emissions were most sensitive to. The results identified that uncertainty in traffic flow speed has a tolerance of ±11 kmh-1 for cars and two-wheelers, and ±24 kmh-1 for HGVs in order to meet the quality framework. Significant variation in emissions were found across surface types, indicating the importance of obtaining representative road surface data. The study found that traffic volumes should be within 60% of their true value. The effect of road gradient was found to be dependent on flow composition and speed. Road traffic noise emissions were found to be insensitive to changes in air temperature. Composite flow analysis using English traffic statistics with various proportions of HGVs showed that these assumptions become more important on lower speed roads, while the proportion of two-wheelers is relatively insignificant with respect to overall noise emissions.

The study of flavonoids accumulation by the herb Polygonum aviculare of the synanthropic flora of the Rostov Region

Aim to study the flavonoid accumulation peculiarities in the birdweed herb (Polygonum aviculare) harvested in the Rostov Region.
 Material and methods. Several raw material sampling areas in the Morozovsky District of the Rostov Region were selected for the study. The birdweed grass was harvested near a major highway M-21 (IA category), a low-speed road (IV category) with little traffic, and a railway line of the North Caucasus Railway. The sampling was conducted at distances from 1 to 300 meters at 100-meter intervals. The choice of harvesting areas was determined by the lack of accurate and reliable information on the accumulation of biologically active substances in the raw material depending on the distance from highways and railroads. In addition, we harvested the birdweed grass in ecologically clean areas far away from the objects of anthropogenic impact (control areas).
 Results. The study of the plant raw material harvested along a low-speed road with little traffic revealed a direct correlation in the reduction of flavonoid content, in terms of avicularin, with increasing distance from the road. The results obtained in the study of samples harvested along the highway M-21 and the railway line also reflected the dependence of the induction of phenolic compounds in the raw material on its growth near the highway. However, in conditions of remoteness from a source of anthropogenic impact on 200 meters and more, there was a decrease in the content of flavonoids, which was approximately equal to their content in the raw material harvested in the control areas.
 Conclusion. A moderate anthropogenic impact, which is characterized by the release of various ecotoxicants into the environment, can induce the biosynthesis of flavonol compounds.

Safer pedestrian crossing facilities on low-speed roads: Comparison of innovative treatments

Despite the international efforts to improve pedestrian safety in different regions of the world, pedestrian fatalities still account for around one-third of annual road traffic deaths. Residential areas are commonly characterized by high pedestrian flows, making pedestrian safety a highpriority public health issue. Different types of treatments such as ITS-based, road markings, and physical treatments have been implemented to improve pedestrian safety, however, their efficiency varies between different locations worldwide. Therefore, this study aims to compare different innovative crosswalk treatments and to investigate their impacts on driving behavior in residential areas using a driving simulator. In our study, we juxtapose five different types of treatments with the untreated control condition. The treatments included two ITS-based solutions [LED pavement lights (ITS_LED) and Variable Message Sign (ITS_VMS)]; two different road markings [yellow zigzag marking (Marking_zigzag) and white road narrowing marking with the word SLOW written in the middle (Marking_narrowing)] and a physical road narrowing treatment (Physical_narrowing). Each of the tested conditions (control condition and treatment conditions) was tested with a Yield/Stop-controlled marked crosswalk located in a residential area with a posted speed limit of 50 km/h for two different situations. In the first situation, there was no pedestrian at the crosswalk (Situation PA), while in the second situation, a pedestrian was present at the crosswalk (Situation PP). Sixty-one volunteers possessing a valid Qatari driving license participated in the experiment. The study results showed that compared to the control condition, Physical_narrowing, ITS_VMS, and Marking_narrowing conditions helped to improve the yielding rates by 12.7 %. In terms of drivers’ speed behavior, even though a pedestrian was not present at the crosswalk in Situation PA, physical_narrowing performed best by lowering the mean travel speed by around 10.1 km/h at the conflict location compared to the control location. Finally, the participants rated the physical_narrowing condition highest among the tested conditions. Based on the findings of the study, we conclude that the physical_narrowing treatment outperform other studied treatments since it significantly limits the freedom of drivers to maneuver, forcing them to slow down and give priority to crossing pedestrians.

Nonlinear MPC-Based Acceleration Slip Regulation for Distributed Electric Vehicles

To address the problem in which wheel longitudinal slip rate directly affects the dynamics and handling stability of a vehicle under driving conditions, front and rear dual-motor four-wheel drive electric vehicles (4WD EVs) were selected as the research object in this study. An acceleration slip regulation (ASR) control strategy based on nonlinear model predictive control (NMPC) is proposed. First, the vehicle dynamics model and the Simulink/CarSim co-simulation platform were built. Second, an ASR controller with intervention and exit mechanisms was designed with the control objective of tracking reference speed or optimal slip rate. Then, considering the problem that the left and right wheels could not freely distribute torque under the condition of a split road surface, the motor output torque was determined in accordance with the wheel with the larger slip rate to enhance passibility. Finally, on the basis of the built Simulink/CarSim co-simulation platform, slip rate control simulation experiments were performed on a snow-covered road, a wet asphalt road, a docking road, and a split road. The designed controller can better track target slip rate and it exhibits better dynamic performance and stability than the method with PID control under different road conditions, especially under low speed and low adhesion road conditions, and its robustness can also meet the requirements.

Factors Affecting Crash Severity among Elderly Drivers: A Multilevel Ordinal Logistic Regression Approach

This study modeled the crash severity of elderly drivers using data from the state of Virginia, United States, for the period of 2014 through to 2021. The impact of several exogenous variables on the level of crash severity was investigated. A multilevel ordinal logistic regression model (M-OLR) was utilized to account for the spatial heterogeneity across different physical jurisdictions. The findings discussed herein indicate that the M-OLR can handle the spatial heterogeneity and lead to a better fit in comparison to a standard ordinal logistic regression model (OLR), as the likelihood-ratio statistics comparing the OLR and M-OLR models were found to be statistically significant, with p-value of <0.001. The results showed that crashes occurring on two-way roads are likely to be more severe than those on one-way roads. Moreover, the risks for older, distracted, and/or drowsy drivers to be involved in more severe crashes escalate than undistracted and nondrowsy drivers. The data also confirmed that the consequences of crashes involving unbelted drivers are prone to be more severe than those for belted drivers and their passengers. Furthermore, the crash severity on higher-speed roads or when linked to high-speed violations is more extreme than on low-speed roads or when operating in compliance with stated speed limits. Crashes that involve animals are likely to lead to property damage only, rather than result in severe injuries. These findings provide insights into the contributing factors for crash severity among older drivers in Virginia and support better designs of Virginia road networks.

Analyzing the spatial determinants of dockless e-scooter & e-bike trips across four U.S. cities

In this study, we examine micromobility usage across four U.S. metropolitan areas, comprising over 3 million people. As micromobility increases in popularity and becomes incorporated in policies and city planning, it is important to understand how disadvantaged and underserved communities utilize shared micromobility options. Underserved communities typically have the lowest access to transportation options and thus, opportunities to jobs, health care, and food. While micromobility has the potential to increase opportunities in low-income areas, it is unclear how people in low-income and high minority areas use these options. Using publicly available API data, we analyze how e-scooters and e-bikes are employed in Los Angeles, Washington, D.C., Detroit, and Louisville. We find that the built environment had a strong impact on both the number of trips within a census block group (CBG) and the duration of those trips. Specifically, pedestrian-friendly intersections (e.g. low-speed roads, bicycle and pedestrian trails) generated more trips than automobile oriented facilities. Presence of fixed transportation and percentage of households with one or less cars had a strong and positive impact on the number of trips. The proportion of minorities and percentage of low-wage employment in a CBG are both negatively associated with trips in all four cities. The results suggest that existing efforts to promote shared micromobility usage in minority and low-income communities may not be sufficient. Designing pedestrian and bicycle-oriented streets, increasing public outreach and promoting access, and enforcing equity zones could increase shared micromobility usage in low-income and minority areas.

What makes bicyclists comfortable? Insights from a visual preference survey of casual and prospective bicyclists

• Comfort in different bicycling environments measured using a visual preference survey. • Bike infrastructure and low traffic speeds generate higher comfort ratings. • People without a predisposition to bicycle are unlikely to feel comfortable with even the best-designed on-road facilities. • Planning for a “design person” and setting a minimum infrastructure standard could increase comfort for all. Understanding what environments are comfortable (and perceived as safe) for bicyclists is essential for increasing bicycling, particularly for non-experienced riders. Surveys probing people’s qualitative perceptions about bicycling environments can inform bicycle planning in important ways. In this study we use survey data from an on-line video experiment to analyze bicycling comfort and its relationship with person-level and road-level variables. We use an existing survey of students, faculty, and staff at UC Davis (n = 3089) who rated video clips of bicycling facilities in different environments based on their perceived comfort as a part of the annual UC Davis Campus Travel Survey (CTS). The video clips come from a variety of urban and semi-rural roads around the San Francisco Bay Area where bicycling rates vary. Our results indicate considerable effects of socio-demographics and attitudes on absolute video ratings, but we find relative agreement about which videos are most comfortable and uncomfortable across our sample population segments. Presence of bike infrastructure and low speed roads are especially important in generating higher comfort ratings. However, our results suggest that even the best designed on-road bike facilities (according to attributes in our data) are unlikely to provide a comfortable bicycling environment for those without a predisposition to bicycle. Nonetheless, our results provide guidance for improving roads with on-street bike facilities where protected or separated facilities may not be suitable. We discuss these results in the context of design standards for bicycling and methods for prioritizing bike infrastructure investments.

Economic impact of 30km/h - Benefits and Costs of Speeds in an urban environment

Speed has fundamental economic costs which are hidden for many stakeholders. On the other hand, the economic benefits of speed are highly visible and strongly promoted by benefiting stakeholders and indeed carefully considered in cost-benefit assessments by road operating agencies. Thus, the main purpose of this paper is to explore and present the benefits and costs of low speed roads in urban environments.

Contrasting wolf responses to different paved roads and traffic volume levels

In some regions of the world, large carnivores, such as wolves, persist in landscapes with dense networks of paved roads. However, beyond the general impacts of roads on wildlife, we still lack information on carnivore responses to different types of roads and traffic volume levels. Using wolves in NW Spain as a case study, we show how wolves respond differently to paved road classes depending on road size, speed limit and traffic volume. All wolves evaluated (25 GPS collared wolves) crossed paved roads. Overall, during 3,915 sampling days, we recorded 29,859 wolf crossings. Wolf crossings of all paved road classes were recorded at a mean rate of 0.022 crossings/day/km (95% CI 0.016–0.027). Wolves crossed low speed and low traffic volume roads more frequently, and more often during the night, in order to lessen the chances of encountering traffic. We found mortality to be highest on roads with high speed and high traffic volume. How wolves interact with paved roads should be considered in landscape planning strategies in order to guarantee wolf long-term persistence in human-dominated landscapes. In our case, our results support an increasing focus on primary roads (class II) to identify segments of these roads where road mitigation efforts should be prioritised. Our study also highlights the importance of considering paved road classes when studying the impact of roads on wildlife.

An investigation of cyclist passing distances in the Australian Capital Territory

In Australia, cycling hospitalisations are increasing and the cycling participation rate is stagnating. In an effort to improve cyclist safety, many Australian jurisdictions have mandated a minimum passing distance that vehicles much provide when overtaking a cyclist on a public road, including the Australian Capital Territory (ACT). However, it is not currently clear how vehicle-cyclist passing distances are affected by various parameters such as the road environment, the vehicles involved, or the speed limit. This naturalistic bicycle riding study examined data from passing distance measurement devices that were installed on the bicycles of volunteer cyclists who ride in the ACT, to explore how passing distances and compliance with the minimum passing distance were affected by several parameters. Over a four-week period, 23 volunteer cyclist participants undertook 465 journeys and travelled 6531 km over a total period of 271 h. There were 10,959 passing events identified on roads zoned greater than 60 km/h (high speed roads) of which 1349 (12.3 %) were non-compliant. On roads zoned 60 km/h or less (low speed roads) there were 5517 passing events of which 153 (2.8 %) were non-compliant. Regression analyses showed that differences in passing distance and non-compliance with the minimum passing distance were associated with road classification, bike lane presence, and speed limit. The results were mixed but, in general, passing distances were greater on roads with a lower (hierarchy) classification and on motorways as well as on roads with higher speed limits. An exception to this was roads with a speed limit of 50 km/h where passing distances were closer in comparison to roads with a speed limit of 60 km/h. Bike lanes were generally associated with an increase in passing distance except on ‘trunk’ classified roads, where a bike lane resulted in closer passing events. This suggests that on trunk roads, which are assumed to carry large amounts of traffic, bike lanes may be insufficient to offer protection to cyclists and additional measures may be required.

Crash Severity Analysis for Low-Speed Roads Using Structural Equation Modeling Considering Shoulder- and Pavement-Distress Conditions

AbstractCrash severity outcomes are random and are influenced by the interactions of vehicle, driver, crash, road, and environmental factors. Limited research has attempted to assess the direct and...

Understanding the correlation between auto-ignition, heat release and knocking characteristics through optical engines with high compression ratio

Improving compression ratio is an effective way to meet higher thermal efficiency and lower CO2 emissions for internal combustion engines. However, the severe thermodynamic condition under low speed and high road may promote the possibility of auto-ignition and damage engine body if it is uncontrollable. Therefore, further study on the correlation between auto-ignition and knocking characteristics are necessary for modern engines with high compression ratio. In this study, combined with high-speed direct photography and simultaneous pressure acquisition, flame images and in-cylinder pressures characterizing auto-ignition, heat release rate and knocking combustion were studied based on optical engine experiments. The results show that auto-ignition occurs in all engine cycles under current critical knocking conditions, and fast SI flame speed cycles is more likely to facilitate end-gas auto-ignition. However, the auto-ignition flame speed is comparable to the SI flame and auto-ignition is not a sufficient condition for knock: for some cycles multipoint auto-ignitions occur near the SI flame front and result in two peak heat release rate, which is beneficial to engine thermal efficiency. Further analysis shows that there is no obvious pertinence between knock intensity and auto-ignition onset while knock intensity strongly depends on the peak HRR per unit volume. High peak HRR per unit volume always results in knocking combustion. The current study shall give insights into utilizing auto-ignition in high compression ratio SI engines.

Pavement serviceability evaluation using whole body vibration techniques: a case study for urban roads

ABSTRACT Quantification of the pavement serviceability is most often based on the international roughness index (IRI). However, in urban environments it can become challenging to drive at 80 km/h as vehicle operating speeds are much lower, among other limitations associated with the use of IRI as an indicator of ride quality in the urban context. This study was conducted to formulate an alternative pavement serviceability evaluation criteria for low-speed roads (30–60 km/h) in urban settings. Deterministic and probabilistic models were developed to predict the PSI based on the whole-body vibration (WBV) concepts, and thereafter, the results were compared with the ISO 2631 standard that addresses human exposure to multiple mechanical shocks. The ISO 2631 standard uses a WBV-based frequency-weighted root-mean-square acceleration parameter (aw ) for evaluating discomfort in a multi-axis environment. Based on the estimated models, an awz criterion of 0.98 m/s2 at a probability acceptance of 85%, for a vehicle operating speed of 50 km/h, was proposed for urban roads in this study. Overall, the study demonstrated that for accurate estimation of ride quality and comfort (i.e. PSI) of low-speed urban roads, the evaluation criteria should be based on low vehicle speeds that are more representative of urban field conditions.