scholarly journals M7 to M2 Pre-congestion Speed Management

2021 ◽  
Vol 32 (4) ◽  
pp. 60-67
Author(s):  
Timothy Clark ◽  
Sam Gray
Keyword(s):  
Traffic Flow ◽  
Reporting System ◽  
Speed Limit ◽  
Speed Limits ◽  
Opportune Time ◽  
Speed Management ◽  
Calming Effect

This paper explores the development and implementation of the M7 to M2 pre-congestion speed limit management trial conducted on workdays between 26th June 2018 and 31st December 2018. This trial was the first of its kind in NSW and was implemented using a live loop reporting system utilising key trigger values (specific loop metrics) to identify the opportune time to reduce speed limits prior to flow breakdown. Through measuring the rate at which speeds dropped during flow breakdown, the heatmap footprint of congestion, and the instance of congestion related crashes it was established the trial was able to have a calming effect on traffic flow and reduce the overall footprint of congestion.

scholarly journals Evaluation of Speeding and Behaviour of Drivers in Roadwork Zones

2018 ◽  
Vol 13 (3) ◽  
Author(s):  
Donatas Čygas ◽  
Dovydas Skrodenis ◽  
Aivaras Paškauskas ◽  
Živilė Sušinskaitė ◽  
Laura Žalimienė
Keyword(s):  
Traffic Flow ◽  
Traffic Safety ◽  
European Countries ◽  
Significant Problem ◽  
Speed Limit ◽  
Work Zones ◽  
Speed Limits ◽  
Safety Measures ◽  
Speed Measurement ◽  
Road Work

Due to the increased traffic flow, more and more roadwork zones are formed in highways. Accidents are a significant problem in all European countries in roadwork zones while noncompliance with speed limits is one of the major safety concerns. Therefore roadwork zones are critical places from the point of traffic safety view where the possibility to get into an accident is increased. Roadwork zones introduce deviations from regular travel situations, and appropriate speed is needed to assure that the driver navigates safely through the roadwork zone. This research focuses on speed measurement in road work zones and attempts to evaluate the effectiveness of safety measures on speed limit compliance.

scholarly journals The Effect of Posted Speed Limit on the Dispersion of Traffic Flow Speed

2019 ◽  
Vol 11 (13) ◽  
pp. 3594 ◽  
Author(s):  
Chao Gao ◽  
Jinliang Xu ◽  
Qunshan Li ◽  
Jie Yang
Keyword(s):  
Traffic Flow ◽  
Flow Speed ◽  
Traffic Volume ◽  
Free Flow ◽  
Speed Limit ◽  
Flow State ◽  
Speed Limits ◽  
Limit Values ◽  
Average Speed ◽  
The Road

Speed dispersion is an important indicator to portray the quality of traffic flow and is closely related to the road safety operation level. In order to clarify the influence of posted speed limits on the dispersion of traffic flow speed, three sections with speed limits of 80 km/h, 100 km/h and 120 km/h on the same expressway were selected for observation, and traffic volume, speed and other parameters were collected. The characteristic speeds, such as average speed, V15 and V85, were evaluation indicators, where V15 and V85 are the speeds of the 15th and 85th percentiles measured at the feature points of the road when the traffic is in a free-flow state and the weather is good. The relationship between different posted speed limit values and the above indicators was analyzed using the statistical analysis software, SPSS. The results show that the speed limit has a high correlation with the average speed of traffic flow, V15 and V85 in free-flow state, with the coefficient of determination being as high as 0.84, 0.85 and 0.92, respectively. In the restricted flow state, the factors affecting the driver’s driving speed are mainly the decrease in driving freedom caused by the increase of traffic volume rather than the speed limit value. In a free-flow state, when the posted speed limit is increased and the average speed and the V85 also increased by approximately the same magnitude. The posted speed limit values of 80 km/h, 100 km/h and 120 km/h correspond to the 90, 88 and 97 percentile speeds of the traffic flow, respectively. The higher the speed limit is, the larger the speed difference between V15 and V85 becomes. The results of the study are very useful for rationally determining the speed limit scheme under different traffic flows.

scholarly journals Modeling of the Relationship Between Speed Limit and Characteristic Speed of Expressway Traffic Flow

2019 ◽  
Vol 11 (17) ◽  
pp. 4621 ◽  
Author(s):  
Jie Yang ◽  
Jinliang Xu ◽  
Chao Gao ◽  
Guohua Bai ◽  
Linfang Xie ◽  
...  
Keyword(s):  
Traffic Flow ◽  
Highway Safety ◽  
Free Flow ◽  
Speed Limit ◽  
Vehicle Speed ◽  
Flow State ◽  
Speed Limits ◽  
Characteristic Speed ◽  
The Relationship ◽  
Strong Linear Relationship

Understanding the relationship between speed limit and characteristic speed of expressway traffic flow is of great significance for formulating a reasonable speed limit scheme and improving highway safety and transportation efficiency. In this study, the speed data of the same traffic flow passing through speed limits of 80, 100, and 120 km/h were continuously collected through a field test. The 85th, 15th, and 50th percentile speeds were considered the characteristic speed parameters of the traffic flow. A regression analysis was performed to establish a relationship between the characteristic speed parameters of the traffic flow and the speed limit. Under a free-flow state, the characteristic speed exhibited a strong linear relationship with the speed limit, where the variation ranges of the 85th and 50th percentile speeds were approximately consistent with that of the speed limit. However, a slight inconsistency was found for the 15th percentile speed, which was approximately half the speed limit increase; under a non-free-flow state, the correlation between the speed limit and the vehicle speed was no longer significant.

Numerical Simulation of Traffic Flow in the Tollgate Area with Variable Speed Limits

2011 ◽  
Vol 130-134 ◽  
pp. 3404-3409
Author(s):  
Wen Xing Zhu ◽  
Zhi Ping Jia
Keyword(s):  
Traffic Flow ◽  
Velocity Model ◽  
Flow Speed ◽  
Open Boundary ◽  
Speed Limit ◽  
Variable Speed ◽  
Variable Speed Limit ◽  
Speed Limits ◽  
Optimal Velocity ◽  
Variable Speed Limits

We investigate behaviors of vehicles passing a controlled area with variable speed limits (VSL) before a tollgate. The traffic flow mathematical model is formulated based on optimal velocity model. The typical sketch of tollgate area is plotted and variable speed limit signs are set in the area to control the traffic flow speed for fear of accident and congestion. Simulations are carried out to examine the influence on traffic flow passing the controlled area with different number of the speed limit signs under open boundary condition. The simulations results show that more speed limit signs may reduce the risk of rear-end collision and the occurrence of the congestion in the tollgate area.

scholarly journals SETTING SPEED LIMITS IN INTERURBAN SINGLE-CARRIAGEWAY HIGHWAYS USING EXPERT’S JUDGMENT

Transport ◽  
2016 ◽  
Vol 31 (2) ◽  
pp. 282-294
Author(s):  
Ana Bastos Silva ◽  
Álvaro Seco ◽  
Nuno Gregório
Keyword(s):  
Decision Making ◽  
Decision Support ◽  
Choice Model ◽  
Selection Process ◽  
Motor Vehicles ◽  
Decision Making Process ◽  
Final Decision ◽  
Speed Limit ◽  
Speed Limits ◽  
Speed Management

Until recently, the design of road infrastructure involved mainly concerns related to the base speed value and to requirements ensuring a high level of service. Currently, it is widely accepted that only an integrated approach is able to take into account the interests and needs of all the involved stakeholders, namely the need of traffic fluidity by motor vehicles, and quality of life and safety associated to other users and local residents. This vision has been leading to different speed management approaches, particularly in relation to the setting of the appropriate and coherent speed limits along extensive routes. In this context, this study is part of a broader research program aimed to develop a methodology of speed management with a widespread use applied to single carriageway roads in interurban areas, crossing different road surrounding environments with varying rural, urban or mixed characteristics. More specifically, this research line is focused on the development of a decision-support methodology for the definition of the appropriate speed limit, based on the drivers’ willingness to naturally accept successive changes in the speed limits in successive stretches of the roads. This decision-making process necessarily involves a broad set of variables and factors that might be divided in two fundamental components: (1) road geometry, and (2) interaction between the road and its surrounding environment. The effect related to the geometric characteristics has already been extensively studied, thus, this paper is focused on speed limit modelling having exclusively into account the latter component, leaving geometryrelated considerations to the final decision-making process. A MultiNomial Logit (MNL) discrete choice model was developed. The modelling work was carried out using a case study involving 55.4 km and 11 km more, for validation purposes – of rural roads crossing different environments. The model was estimated based on the judgments of fourtraffic safety experts applied to each direction of each road stretch (200 m long). Before the modelling development, a factor analysis involving the whole set of variables was carried out, in order to detect not directly observable common features on its structure that may influence the final outcome of model estimation. This analysis allowed to corroborate the overall variable selection process. The developed model adjusts quite well to the data with McFadden pseudo-R2 of 0.447. Without loss of explaining power it was possible to avoid the presence of subjectivity related to a qualitative evaluation of some explanatory variables, greatly enhancing the model’s robustness and transferability to other locations and countries. The new modelling structure also facilitates the interpretation of the validation results and enables the models to be developed to represent different levels of safety related sensitivity existent amongst the expert community, by using a ‘conservative expert’ evaluation. The results validation has showed the models to be robust and useful as decision support tools applied to speed limits’ evaluation processes.

scholarly journals Effects of reducing and enforcing speed limits in selected arterial roads in Bogota

2021 ◽  
Vol 8 (2) ◽  
pp. 50-71
Author(s):  
José Segundo López ◽  
David Perez-Barbosa ◽  
Natalia Lleras ◽  
Darió Hidalgo ◽  
Claudia Adriazola-Steil
Keyword(s):  
Geographical Distribution ◽  
Speed Limit ◽  
Traffic Crashes ◽  
Speed Limits ◽  
Speed Reduction ◽  
Average Speed ◽  
Management Measure ◽  
Speed Management ◽  
The City

In Bogota, the speed limit in five corridors with the highest concentration of traffic crashes victims in the city was reduced from 60 to 50 km/h since November 2018. The average speed reduction in the corridors with speed management was 1.48 km/h during daytime and 3.04 km/h during nighttime. In arterial corridors without speed management, the average speed reduction was 0.7 km/h during daytime and 2.2 km/h during nighttime. The speed management measure influenced a reduction of 16.6% in the number of fatalities and an 10.5% increase of crashes with injuries. The severity of the crashes decreased. The average count of run over crashes was also reduced by 10%. Changes in the geographical distribution of crashes with injuries and fatalities along the corridors with speed management indicate the necessity to implement stricter enforcement measures to increase the effectiveness of speed management operations during nighttime.

scholarly journals Effects of higher maximum speed limits to vehicle speeds: A before - after analysis on rural divided highways in Vietnam

2018 ◽  
Vol 12 (3) ◽  
pp. 132-137
Author(s):  
Do Duy Dinh ◽  
Thai Hong Nam ◽  
Vu Hoai Nam
Keyword(s):  
Traffic Safety ◽  
Maximum Speed ◽  
P Value ◽  
Speed Limit ◽  
Speed Limits ◽  
Wide Range ◽  
Before And After ◽  
Speed Management ◽  
The Mean ◽  
Very High

This study is to assess the effects of raising speed limits to vehicle operating speeds on rural divided highways in Vietnam. Vehicle speeds were recorded at three different sites of three routes during the daytime and nighttime, both before and after speed limits on these sites increasing from 80 km/h to 90 km/h. The results have shown that the percentage of speeds exceeding speed limits had a wide range from 0% to nearly 30% with regard to different locations, survey time and speed limits. The extent of speeding in some cases was very high even after speed limit increased. It was found that in most cases, the changes in mean speeds after a higher speed limit was applied were statistically significant at the p-value of 0.05, however, the magnitudes of the mean change varied considerably between locations and survey times. Because four out of six cases under the study having mean speeds increased by over 10 km/h after setting up a higher speed limit, this study suggests that further appropriate measures of speed control and speed management should be applied along with increasing speed limit to ensure traffic safety on rural divided highways in Vietnam. Article history: Received 27 March 2018, Revised 18 April 2018, Accepted 27 April 2018

scholarly journals Evaluating the Impacts of Speed Limit Increases on Rural Two-Lane Highways Using Quantile Regression

2021 ◽  
pp. 036119812110197
Author(s):  
Md Shakir Mahmud ◽  
Nischal Gupta ◽  
Babak Safaei ◽  
Hisham Jashami ◽  
Timothy J. Gates ◽  
...  
Keyword(s):  
Quantile Regression ◽  
Spillover Effects ◽  
Speed Limit ◽  
Passenger Cars ◽  
Cross Sectional ◽  
Speed Limits ◽  
Site Specific ◽  
Rural Highways ◽  
Speed Selection ◽  
Numerous Site

Understanding speed selection behavior of drivers following speed limit increases is critically important. To date, the literature has largely focused on freeways and the effects of speed limit changes on two-lane highways remains under researched. Prior research has generally focused on changes to mean speeds, although the speeds of both the highest and lowest drivers are also of great interest. This study investigates trends in free-flow travel speeds following 2017 legislation that increased the posted speed limit from 55 to 65 mph on 943 mi of rural highways in Michigan. Speed data were collected for over 46,000 drivers at 67 increase segments where speed limit increased and 28 control segments where speed limits remained unchanged, before and during each of the two successive years following the speed limit increases. Site-specific traffic, geometric, and cross-sectional information was also collected. Impacts of the speed limit increases on the 15th, 50th, and 85th percentile speeds were evaluated using quantile regression. Separate analyses were conducted for passenger cars and heavy vehicles. Locations where the speed limits were raised experienced increases in travel speeds ranging from 2.8 to 4.8 mph. The control sites experienced marginal changes in speeds, which suggests that any spillover effects of the higher speed limits have been limited. Significant differences were observed across the quantiles with respect to the effects of the speed limit increases, as well as numerous site-specific variables of interest. The results provide important insights about the nature of driver speed selection and the impacts of speed limit increases.

scholarly journals European birds adjust their flight initiation distance to road speed limits

2013 ◽  
Vol 9 (5) ◽  
pp. 20130417 ◽  
Author(s):  
Pierre Legagneux ◽  
Simon Ducatez
Keyword(s):  
Habitat Structure ◽  
Territory Size ◽  
Speed Limit ◽  
Vehicle Speed ◽  
Flight Initiation Distance ◽  
Speed Limits ◽  
Behavioural Responses ◽  
Road Speed ◽  
Flight Initiation ◽  
Local Speed

Behavioural responses can help species persist in habitats modified by humans. Roads and traffic greatly affect animals' mortality not only through habitat structure modifications but also through direct mortality owing to collisions. Although species are known to differ in their sensitivity to the risk of collision, whether individuals can change their behaviour in response to this is still unknown. Here, we tested whether common European birds changed their flight initiation distances (FIDs) in response to vehicles according to road speed limit (a known factor affecting killing rates on roads) and vehicle speed. We found that FID increased with speed limit, although vehicle speed had no effect. This suggests that birds adjust their flight distance to speed limit, which may reduce collision risks and decrease mortality maximizing the time allocated to foraging behaviours. Mobility and territory size are likely to affect an individuals' ability to respond adaptively to local speed limits.

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