Lane Configurations Research Articles

Selection of Intersection Control Type in Urban Areas

Abstract In Egypt, urban planning projects usually do not consider the intersection type. This study developed charts for practitioners that could be used to determine the optimal intersection. The paper studied intersections including; signalized, roundabout, and two-way stop control. It provides a study for the intersection at the targeted level of service D. The traffic patterns were used to calculate the intersection’s capacity and the average control delay. The combinations of turning distribution, percent of heavy vehicles, and type of control were considered. The relationship among capacity, delay and traffic volume has been used to deduce the minimum required lane configuration for each intersection. The results indicated that the roundabout is the best alternative for intersection control with maximum capacity and minimum delays for medium traffic. However, signalized intersection is the best alternative at heavy traffic volumes and a high proportion of left-turning volume.

Investigating the effects of travel lane configuration and lane width on traffic safety where powered-two-wheelers (PTWs) share with larger vehicles: A micro perspective

The design of travel lane configuration and lane width is crucial to traffic safety, especially in an urban mixed traffic environment where Powered-Two-Wheelers (PTWs) are prevalent and share the same roads with larger vehicles such as cars, buses, and trucks. However, there have been limited studies on the effects of the design of travel lane configuration and lane width on safety in such a mixed traffic environment. It’s true the above-mentioned research question can be evaluated simply in terms of the number of crashes. However, doing so not only requires a few years of crash and traffic data, but limited insight can be gained in terms of how driver and rider behaviours are affected, and this has implications for further improvement in road safety. This study examines the changes in driving/riding behaviours and surrogate events before and after the adjustments of travel lane configuration and lane width by proposing a micro perspective approach as a complement to conventional studies. A before-and-after site-based investigation was conducted at two study sites which had opposite adjustments for travel lane configuration and lane widths: at one site the number of lanes was reduced, thereby widening the lane width in the outer lane on one road section, and at the second site the number of lanes was increased, thereby narrowing lane width in the outer lane on the other road section. The results showed that an increase in lane width resulted in a considerable increase in the number of speeding events as well as unsafe driving/riding behaviours and surrogate events related to lane splitting, lane sharing, and overtaking.

Impact of connected and autonomous vehicle dedicated lane on the freeway traffic efficiency

BackgroundThe imminent emergence of connected and autonomous vehicles (CAVs) highlights the need for preparing the road infrastructure for traffic flows mixed with CAVs and human-driven vehicles. A dedicated lane (DL) for CAVs is one of the practical and potential ways to upgrade the road infrastructure for the mixed traffic.MethodsThis paper proposes a theoretical method to discuss the influence of implementing a CAV DL policy on the freeway traffic efficiency. In detail, the impact was measured by capacity and throughput. The calculation methods of these efficiency measurements under different CAV DL policies were proposed.ExperimentsNumerical experiments were conducted under various compositions of CAV DL policies and traffic conditions. More specifically, the relationship between the traffic conditions (i.e., traffic demand, market penetration rate (MPR) of CAVs, platoon intensity of CAVs, willingness of CAVs using the CAV DL) and the CAV DL policies (i.e., lane configuration, DL access control policy) were discussed.Results and ConclusionThe results have led to some interesting findings, including the critical values of MPR that are valuable to guide an appropriate implementation of a CAV DL policy under a specific traffic condition.

Multi-rhythm control for heterogeneous traffic and road networks in CAV environments

Heterogeneity is widely observed in various aspects of urban transport, such as road types, vehicle dynamics, and demand patterns, which greatly complexifies transport systems and hinders the successful control and management of traffic. On one hand, intelligent strategies are required to relieve the loss of efficiency caused by the mixed traffic flow composed of vehicles with different speeds; on the other hand, the spatial heterogeneity of travel demand distribution requires pertinent control schemes to improve the network-level mobility and the phenomenon of oversaturation under heavy traffic also demands an appropriate way to resolve. Leveraging the advantages of connected and automated vehicle (CAV) technology, this study proposes a multi-rhythm control (MRC) scheme to accommodate heterogeneous network traffic in a CAV environment with 100% penetration rate. While the rhythmic control (RC) proposed by (Lin et al., 2021) could organize traffic efficiently and in an orderly manner, the multi-rhythm strategy has greater potential to not only improve the efficiency of heterogeneous traffic by the design of different virtual platoons (VPs) catering to different vehicle types, but also address the spatial heterogeneity of network traffic by implementing differentiated cycle lengths among the road network. For the optimal design of the MRC scheme, a two-step model is developed to minimize the total travel cost, where the first step focuses on the mesoscopic level to jointly optimize the multi-rhythm scheme, VP design and lane configuration for both undersaturated and oversaturated cases, while the second step focuses on the microscopic design to optimize the space–time trajectories of VPs under the premise of collision free. Numerical examples and simulation experiments are conducted to test the performances of the MRC scheme compared to a naive version of RC with a homogeneous rhythm and a traffic signal control (TSC) strategy. The results show that among all control strategies, the MRC scheme has the best performance under all kinds of demand patterns, which is reflected in both the lowest travel cost and the highest network throughput.

Safety impacts of geometric design on freeway segments with closely spaced entrance and exit ramps

The objective of this study was to evaluate the effects of geometric design on crash risk on freeway segments with closely spaced entrance and exit ramps. Traffic flow, geometric design features and crash data from 80 segments on 14 freeways in the state of California, United States were applied. A multilevel logistic regression model with cross-level interactions was developed, where traffic variables were put on the case level, and their estimated coefficients were defined as a function of geometric design variables on the segment level. A basic logistic model and a multilevel logistic model without cross-level interactions were developed for comparison. The result shows that the one with cross-level interactions provides the best goodness of fit. The results indicate that six categories of geometric design variables are significantly associated with crash risk, i.e. lane configuration, basic number of lanes, ramp spacing, theoretical gore, inner shoulder width and speed limit. All but one (inner should width) geometric design variables have significant interaction terms with traffic flow variables. The effects of geometric design variables on crash risk are not fixed but vary with traffic conditions. The findings of this study can provide design guidance to improve road safety of freeway segments with closely spaced entrance and exit ramps.

Implementation Sequence Optimization for Dedicated Bus Lane Projects

Transportation projects are often implemented in phases, and the total project duration can span years. Optimization of the sequence in which transportation projects are implemented can decrease the severity of disruptions caused by construction, reduce the total cost of projects, and increase the present value of the benefits of the project. This paper presents a method for optimizing the sequence and location of dedicated bus lane implementations. The proposed method is based on a bi-level optimization framework. The lower level simulates the traffic using a link transmission model to evaluate car and bus delays, while the upper level optimizes the locations of bus lanes and/or the implementation sequence of a given bus lane configuration. If the budget or other resource constraints are binding, the optimized sequence uniquely determines the optimal schedule. The solution method is evaluated for a test network, and an analysis of sensitivity to different demand patterns and different bus lane configurations is conducted. First, the optimized locations for bus lane implementation are determined for an illustrative test network. Results suggest that, when considering the implementation sequence for the optimized set of bus lane locations, the sequence of implementation does not yield significant benefits. However, if bus lanes are implemented on every possible link, the results suggest that prioritizing the implementation of bus lanes on peripheral links would reduce the total cost the most. These locations coincide with the set of optimized locations for bus lane implementation. Further tests considering non-uniform demand patterns also confirm these findings.

Model of emergence evacuation route planning with contra flow and zone scheduling in disaster evacuation

Evacuation is characterized by rapid movement of people in unsafe locations or disaster sites to safer locations. The traffic management strategy for commonly used evacuations is the use of Shoulder-Lane, contra flowing traffic and gradual evacuation. Contra flowhas been commonly used in traffic management by changing traffic lanes during peak hours. To implement the contra flowoperation, there are two main problems that must be decided, namely optimal contraflow lane configuration problem (OCLCP) and optimal contraflow scheduling. Within the OCSP there are two approaches that can be used: zone scheduling and flow scheduling. Problem of contra flow and zone scheduling problem is basically an emergence evacuation route planning (EERP) issue. This research will discuss EERP with contraflow and zone scheduling which can guarantee the movement of people in disaster area to safe area in emergency situation.

Model of emergence evacuation route planning with contra flow and zone scheduling in disaster evacuation

Evacuation is characterized by rapid movement of people in unsafe locations or disaster sites to safer locations. The traffic management strategy for commonly used evacuations is the use of Shoulder-Lane, contraflowing traffic and gradual evacuation. Contra-flow has been commonly used in traffic management by changing traffic lanes during peak hours. To implement the contra-flow operation, there are two main problems that must be decided, namely Optimal Contraflow Lane Configuration Problem (OCLCP) and Optimal Contraflow Scheduling. Within the OCSP there are two approaches that can be used: zone scheduling and flow scheduling. Problem of Contra Flow and Zone Scheduling Problem is basically an Emergence Evacuation Route Planning (EERP) issue. This research will discuss EERP with ContraFlow and Zone Scheduling which can guarantee the movement of people in disaster area to safe area in emergency situation.

Future Traffic Prediction from Short Period Traffic Data

Prediction of future traffic is a complicated process which requires logical prediction methods and experience. The present study focused on the prediction of future traffic from the AADT data which is estimated from the one week continuous traffic data collected from the selected study area. State wise traffic contributions are estimated from the one-day number plate survey data and major states effecting the traffic in the study area are observed. The population data, vehicle registration data and economic data of the major states which are observed through number plate survey are used for the prediction of future traffic data. The vehicle growth rates were calculated using average vehicle registration growth rate method and nonlinear regression (power regression). Finally, the growth rates were decided according to the traffic design norms provided by NHAI. The year wise future traffic was predicted and presented in this paper from the year 2013 to 2040. The changes in Level of Service (LOS) of the NH 8A for four lane and six lane configuration is detailed for the future scenario.

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.

Toll Plaza Lane Choice and Lane Configuration Strategy for Autonomous Vehicles in Mixed Traffic

Toll plazas are one kind of highway node that pose a challenge to the flow of autonomous vehicles (AVs). Some toll roads have open road tolling (ORT), which makes it easier and more efficient for AVs, but most toll plazas do not have ORT. The authors developed a decision model to assist AVs in choosing the right lane that involves two main indicators, the rod speed (SRi) and the decision-making value (DSRi). The decision model was applied to a six-lane toll plaza with manual toll collection (MTC), electronic toll collection (ETC), and electronic toll collection for AVs toll types. The suitable lane configurations for the varying percentages of AVs in traffic were as follows: at 10% AV, the optimal lane configuration was 4 MTC and 2 ETC/AV (4M2EA), at 30% AV it was 3M3EA, at 40%–60% AV it was 3M2EA1A, and at 70% AV it was 2M2EA2A. Thus AVs should share toll lanes with ETC manned vehicles before the population of AVs reaches 30%; after that dedicated lanes may be introduced. It was also concluded that a 10% increase in AVs reduces delays by 9% if the populations of ETC and MTC vehicles are equal.

Safety and operational impact of connected vehicles’ lane configuration on freeway facilities with managed lanes

Managed lanes (MLs) have been implemented as a vital strategy for traffic safety and management improvements. Previous studies involving MLs didn’t examine the impact of connected vehicles’ (CVs) lane configuration on freeway facilities with managed toll lanes. CVs are quickly expanding in the transportation industry and are among the most recent promising developments in traffic and safety engineering. In this study, several scenarios were tested using microscopic traffic simulation to determine the optimal CV lane configuration strategies while taking into consideration the market penetration rate (MPR%) of CVs and traffic conditions (i.e., peak, off-peak). Both safety (i.e., conflict frequency, conflict reduction) and operational (i.e., average speed, average delay) performance measures were included in the analyses. A Negative Binomial model was developed for investigating the factors that affect the safety measures. Tobit models were used to evaluate traffic operation. The results of the safety and operational analyses suggested that an MPR% between 10 % and 30 % was recommended when the CVs were only allowed in MLs. By converting one of the general-purpose lanes (GPLs) to a managed lane, the MPR% could reach 60 %. It was also concluded that restricting CVs to only the CV lane was not recommended. Lastly, the findings suggested that by allowing CVs to use all the lanes in the network (MLs, GPLs and CV lane), the optimal MPR% could reach between 70 % and 100 %. This study has major implications for improving MLs by recommending the optimal CV lane configuration and market penetration rate for each design.

Characterization of Mobile Work Zone Safety in Missouri

Work zones often deviate from normal conditions in terms of geometrics (e.g. lane closure, narrow lanes), striping/markings, signs, and traffic. A Mobile Work Zone (MWZ) is a special category of a work zone where the location of the work zone keeps changing, often rapidly. Despite MWZ safety being of great interest to transportation agencies, they have not studied it formally. This paper presents an examination of MWZs and collisions involving Truck-Mounted Attenuators (TMAs). This examination utilized data fusion of three major databases from Missouri: crash reports, department of transportation claim reports, and MWZ schedules. The fused dataset involved 139 crashes from 2012-2017. The areas of interest included initial impact location, contributing factors, third-party versus employee fault, vehicle type, work zone activity, seasonality, speed limit, time of day, collision lane, and work train configuration. The majority of the crashes were the fault of third parties (>80%) and distraction/inattentiveness was the largest contributory factor (66%). Public outreach and education should emphasize on the difficulty in providing early warnings of MWZs. There is a significant percentage of crashes involving lane changing (39.2%) and even collision of the middle TMA truck (21.8%). Thus, it is important for the public to understand that an entire work train is an integral unit. Higher speed limit dominated MWZ crashes (>75%), even though they only represented 3.6% of the MWZs scheduled. The results of this study on MWZs provide some foundation for other researchers to pursue statistical modeling, assuming that a larger database of MWZ crashes could be developed.

Demand prediction and dynamic workforce allocation to improve airport screening operations

Workforce allocation and configuration decisions at airport security checkpoints (e.g., number of lanes open) are usually based on passenger volume forecasts. The accuracy of such forecasts is critical for the smooth functioning of security checkpoints where unexpected surges in passenger volumes are handled proactively. In this article, we present a forecasting model that combines flight schedules and other business fundamentals with historically observed throughput patterns to predict passenger volumes in a multi-terminal multi-security screening checkpoint airport. We then present an optimization model and a solution strategy for dynamically selecting a configuration of open screening lanes to minimize passenger queues and wait times that at the same time determine workforce allocations. We present a real-world case study in a US airport to demonstrate the efficacy of the proposed models.

The Reversible Lane Network Design Problem (RL-NDP) for Smart Cities with Automated Traffic

With automated vehicles (AVs), reversible lanes could be a sustainable transportation solution once there is vehicle-to-infrastructure connectivity informing AVs about the lane configuration changes. This paper introduced the reversible lane network design problem (RL-NDP), formulated in mixed-integer non-linear mathematical programming—both the traffic assignment and the reversible lane decisions were embedded. The model was applied on an hourly basis in the case study of the city of Delft, the Netherlands. Reversible lanes are examined under no traffic equilibrium (former paths are maintained); user-equilibrium (UE) assignment (AVs decide their own paths); and system-optimum (SO) traffic assignment (AVs are forced to follow SO paths). We found out that reversible lanes reduce congested roads, total travel times, and delays up to 36%, 9%, and 22%, respectively. The SO scenario was revealed to be beneficial in reducing the total travel time and congested roads in peak hours, whereas UE is equally optimal in the remaining hours. A dual-scenario mixing SO and UE throughout the day reduced congested roads, total travel times, and delay up to 40%, 8%, and 19%, respectively, yet increased 1% in travel distance. The spatial analysis suggested a substantial lane variability in the suburbs, yet a strong presence of reversible lanes in the city center.

Effect of the Parking Lane Configuration on Vehicle Speeds in Home Zones in Poland

Nowadays, traffic calming measures that are designed to influence the drivers’ behaviour in the first place and thus make them slow down (and increase the safety of traffic as a result) are used increasingly often in traffic engineering. As a rule of thumb, carefully planned street geometry and street furniture should advise the drivers of the traffic calmed area ahead of them, which makes them reduce the vehicle speed by influencing their perception. One of the most common treatments are road narrowings and horizontal deflections of the route of travel. The reduction of the vehicle speed increases the driver’s central visual area, which results in earlier and easier spotting of pedestrians that are about to cross the roadway. A reduction of noise and exhaust emissions is an additional benefit. However, the current sustainable design guidelines are not specific regarding how often the route should be deflected by alternate parking lanes and how frequently they should be placed in the home zones (woonerven in Dutch) in order to achieve the desired reduction of vehicle speed, noise, pollution, and exhaust emissions. This being so, the authors carried out a speed survey research on a chosen street that includes woonerf design features, as typically used in Poland, with carriageway narrowings being created by parking lanes differently sited along its length. Several speed measuring devices were deployed to automatically and simultaneously measure and record the vehicle speeds and volume of traffic at different test locations. The measurement data were subjected to statistical analyses, including conventional statistical tests. The alternative hypothesis, proposing that the vehicle speeds depend on the configuration of parking lanes and carriageway narrowings was confirmed in almost all cases. The results have confirmed that the siting of parking lanes is a relevant factor as far as speed reduction is concerned, with the degree of this reduction depending on the remaining travel lane width.

Safety Performance Functions for Fatal Crashes on National Highways in India

This paper investigates factors contributing to fatal crashes on three National Highways (NHs) sections in India by developing safety performance functions. The generalized linear model technique is used for analysing linear and non-linear effect of continuous and categorical predictor variables on discreet dependent variable (fatal crashes) separately for each NH segments. In India, NHs are not usually access controlled, and heterogeneous vehicles travel on highways. The probable explanatory variables are short-listed after thorough literature review, and availability of data. These variables comprise of vehicular traffic (ADT), highway elements, and roadside land use. The fatal crash data for the past five years (2009-2013), traffic and highway inventory data have been collected for three NHs having varying lane configuration: two-lane NH-8, four-lane NH-24 and six-lane NH-1. The study results revealed negative binomial regression model fit the data statistically, and also identified number of statistically significant variables (‘segment length’, ‘roadside land use’, ‘presence of service road (SR)’ and ‘terrain type’) to estimate fatal crashes at NHs segments. The results of the safety performance functions (SPFs) showed that out of seven explanatory variables examined for each NH (segments), the significant explanatory variable is found to be ‘segment length’ in km for all three models of NHs (segments). Other significant variable is ‘land use’ along NHs for both two-lane NH-8 and four-lane NH-24. Similarly, the explanatory variables ‘presence of SR’ and ‘terrain type’ are found significant for four-lane NH-24 and two-lane NH-8 respectively. ADT (in vehicles) being an important variable in fatal crash modeling, is kept as an offset variable in each model.

Operating Performance of Diverging Diamond Interchanges

As the result of changing traffic patterns, many conventional intersections and interchanges can no longer accommodate growing traffic volumes and heavy turning movements. In response, there are various innovative intersection and interchange designs proposed and implemented to better accommodate these changes, and the diverging diamond interchange (DDI) is one of these alternatives. While there is a significant amount of research on the relative performance of DDIs and conventional diamond interchanges (CDIs), a clear set of guidance on demand conditions under which a DDI is likely an operationally more efficient solution is not readily available. This effort conducts a sensitivity analysis of CDI and DDI operational performance under various interchange lane configurations, including the selected study area of the Jimmy Carter Boulevard and I-85 interchange in Norcross, Georgia, under varying traffic demands and turn-movement ratios. The sensitivity analysis explores the detailed conditions in which one interchange configuration provides superior performance over the other. The sensitivity analysis is structured into a two-step process with a critical lane volume (CLV) analysis as the first step, followed by a VISSIM microscopic simulation study as the second step. Overall, the study found that a CDI is likely to be the preferred option at locations with traffic volumes well below capacity and cross-street left-turn traffic proportions below 30% of the total cross-street demand, and a DDI is likely to be preferred at locations with traffic volumes near capacity and cross-street left-turn proportions exceeding 50% of the total cross-street demand.

Intersection Operation with Non-Traditional Dynamic Lane Scheme through Vehicle-to-Signal Connection

This paper proposes an information-based dynamic lane (IDYL) scheme for signalized intersections with exclusive left-turn phases. Similar to the tandem design, the proposed scheme aims to increase the capacity of an isolated intersection by sorting incoming vehicles based on their turning movements. Its novelty is to guide vehicles of different movements into pre-designated dynamic lanes without stopping them via pre-signal. The assumption is that vehicles themselves or their drivers have access to, and can act on, real-time signal timing information through vehicle-to-signal connection to select the correct lane to enter as they approach the intersection. A mixed integer program is proposed to optimize jointly the lane configuration, timing plan, and dynamic lane utilization for an intersection. Results from numerical and simulation experiments show that IDYL can increase the reserve capacity by more than 25% when implemented on all legs of a standard four-leg intersection, and reduce the delay by around 15% when implemented on two opposing legs. The results from this study could help traffic engineers to operate signalized intersections with dynamic lanes when vehicle-to-signal connection becomes widely available in the near future.

Improving Mobility on Segments with Closely Spaced Intersections in Urban Areas

In this research, a strategy to improve mobility and reduce delay on road segments is explored via modeling and simulation. Thirty selected corridors with combination of signalized and unsignalized intersections were identified for this study. Each segment consists of at least one AWSC and two signalized intersections at which field data were obtained (lane configurations, signal timing, traffic volumes, etc.). The selected AWSC intersections on the segments were within 305 m (1000 feet) from the upstream or downstream signalized intersections. Synchro software program was utilized to model the existing condition of the segments based on which the strategy for mobility improvement was explored. The field data were used as input in Synchro software application to model two scenarios: existing or the “before” scenario, and the “after” scenario. The unsignalized intersections were signalized (and optimized) in the “after” scenario. The measures of effectiveness used to assess the efficiency of the strategy were average travel speed, control delay and 95th percentile queue length. The analyses were conducted for both the morning (AM) and evening (PM) peak periods. The results of the analyses showed reductions in control delay and 95th percentile queue lengths that were statistically significant, while the average travel speed of vehicles significantly increased at 5% level of significance. The evaluation determined that the signalization of some unsignalized intersections (which are 305 m or less from existing signalized intersections) may improve mobility despite the fact that these locations do not meet the MUTCD warrants for signalization. These findings would aid transportation engineers and planners to consider and evaluate this option when making decisions on signalization of intersections in urban areas.