Work Zone Safety Performance: Comparison of Alternative Traffic Control Strategies

2017 ◽  
Vol 2617 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Emira Rista ◽  
Timothy Barrette ◽  
Raha Hamzeie ◽  
Peter Savolainen ◽  
Timothy J. Gates
Keyword(s):  
Traffic Safety ◽  
Traffic Control ◽  
Control Strategies ◽  
Safety Performance ◽  
Work Zone ◽  
Segment Length ◽  
Crash Rates ◽  
Study Results ◽  
Significant Difference ◽  
Lane Closures

Work zone temporary traffic control strategies generally affect both traffic safety and operations. However, there is a substantial gap in the knowledge base with respect to the safety impacts of various work zone characteristics. The Highway Safety Manual provides crash modification functions that account for the effects of project length and duration on crash frequency as compared with normal road operations. However, these methods do not allow for explicit comparisons of expected safety performance among different work or closure types. This research examined the safety impacts of various temporary traffic control strategies on freeways, including shoulder closures, lane closures, and lane shifts. Data were collected for the periods during which these treatments were in effect and during similar nonconstruction periods from the preceding year. Safety performance functions were estimated that account for segment length, duration, traffic volume, and closure type. Random parameter count data models were estimated to accommodate segment-specific temporal correlation and unobserved heterogeneity. Crash rates were shown to vary roughly in proportion to traffic volumes. In contrast, segment length and project duration showed inelastic effects; this finding implies that crash rates increase more rapidly in work zones that are shorter in length or duration. Single-lane closures, multilane closures, and lane shifts were associated with an increase in crashes, whereas shoulder closures did not show a significant difference compared with similar, non-work-zone conditions. Ultimately, the study results provide important information that can be used to assess the crash risk for various temporary traffic control strategies.

Evaluation of the effectiveness of single-lane two-way traffic control at maintenance and reconstruction zones

2006 ◽  
Vol 33 (9) ◽  
pp. 1217-1226 ◽  
Author(s):  
Ahmed Al-Kaisy ◽  
Eric Kerestes
Keyword(s):  
Adaptive Control ◽  
Traffic Control ◽  
Control Strategies ◽  
Stochastic Approach ◽  
Fixed Time ◽  
Work Zone ◽  
Average Delay ◽  
Zone Length ◽  
Time Control ◽  
Study Results

This paper presents a study on evaluating traffic control at single-lane closures on two-lane two-way highways. Four traffic control strategies were investigated by this study. Those strategies involved fixed-time control, fixed-queue control, "static optimum" or convoy rule, and adaptive control. Traffic control strategies were modeled using two approaches; a deterministic approach in spreadsheet application and a stochastic approach in microscopic traffic simulation. Parametric analyses were performed using several variables that are related to traffic control at this type of lane closure. Those variables involved work zone length, average speed at work zone, lost time, traffic level, directional split, and interruptions to traffic by movement of construction vehicle and (or) equipment into and out of the construction site. Study results suggest that significant savings in average delay can be accrued by using more advanced traffic control strategies. Those savings could be as high as 53% for the range of conditions investigated by this research.Key words: work zone, flaggers, adaptive control, simulation, optimization.

scholarly journals Improved Road Safety at Work Zones using Advanced Traveler Information Systems

2020 ◽  
Author(s):  
Mustafa Suhail Almallah ◽  
Qinaat Hussain ◽  
Wael K. M Alhajyaseen ◽  
Tom Brijs
Keyword(s):  
Traffic Safety ◽  
Driving Simulator ◽  
Work Zone ◽  
Speed Limit ◽  
Work Zones ◽  
Treatment Scenario ◽  
Lane Changing ◽  
Variable Message Signs ◽  
Study Results ◽  
Message Signs

Work zones are road sections where road construction or maintenance activities take place. These work zones usually have different alignment and furniture than the original road and thus temporary lower speeds are adopted at these locations. However, drivers usually face difficulty in adopting the new speed limit and maneuvering safely due to the change in alignment. Therefore, work zones are commonly considered as hazardous locations with higher crash rates and severities as reported in the literature. This study aims to investigate the effectiveness of a variable message signs (VMSs) based system for work zone advance warning area. The proposed system aims at enhancing driver adaptation of the reduced speed limit, encourage early lane changing maneuvers and improve the cooperative driving behavior in the pre-work zone road section. The study was conducted using a driving simulator at the College of Engineering of Qatar University. Seventy volunteers holding a valid Qatari passenger car driving license participated in this study. In the simulator experiment, we have two scenarios (control and treatment). The control scenario was designed based on the Qatar Work Zone Traffic Management Guide (QWZTMG), where the length of the advance warning area is 1000 m. Meanwhile, the treatment scenario contains six newly designed variable message signs where two of them were animation-based. The VMSs were placed at the same locations of the static signs in the control scenario. Both scenarios were tested for two situations. In the first situation, the participants were asked to drive on the left lane while in the second situation, they were instructed to drive on the second lane. The study results showed that the proposed system was effective in motivating drivers to reduce their traveling speed in advance. Compared to the control scenario, drivers’ mean speed was significantly 6.3 and 11.1 kph lower in the VMS scenario in the first and second situations, respectively. Furthermore, the VMS scenario encouraged early lane changing maneuvers. In the VMS scenario, drivers changed their lanes in advance by 150 m compared to the control scenario. In addition, the proposed system was effective in motivating drivers to keep larger headways with the frontal merging vehicle. Taking into account the results from this study, we recommend the proposed VMS based system as a potentially effective treatment to improve traffic safety at work zones.

Field Evaluation of Late Merge Traffic Control in Work Zones

2005 ◽  
Vol 1911 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Andrew G. Beacher ◽  
Michael D. Fontaine ◽  
Nicholas J. Garber
Keyword(s):  
Field Test ◽  
Traffic Control ◽  
Positive Response ◽  
Field Evaluation ◽  
Field Studies ◽  
Work Zone ◽  
Work Zones ◽  
Short Term ◽  
Term Field ◽  
Lane Closures

The traffic control strategy of the late merge in work zones was devised to improve flow and safety at work zone lane closures. Although some states have put the strategy into practice, only a handful of short-term field studies have formally evaluated its effectiveness. Additional field studies were necessary to assess the efficacy of the strategy and its proper deployment. This paper documents the results of a field test of the late merge traffic control conducted over several months. The late merge strategy was evaluated by comparing its effectiveness with that of traditional plans for work zone lane closures. The field test was conducted on a primary route in Tappahannock, Virginia, at a two-to-one lane closure. Results showed that throughput increased, but the increase was not statistically significant. Likewise, time in queue decreased, but the decrease was not statistically significant. These results were much less dramatic than those of other studies. Possible reasons for this disparity include different driver populations, road types, vehicle mixes, and site-specific characteristics. Despite limited improvements in throughput and time in queue, more drivers were in the closed lane, a positive response to the late merge signs.

scholarly journals Urban Intersections and Traffic Safety in the City of San Antonio

2019 ◽  
Vol 271 ◽  
pp. 06003
Author(s):  
Qasim Adegbite ◽  
Khondoker Billah ◽  
Hatim Sharif ◽  
Samer Dessouky
Keyword(s):  
Traffic Safety ◽  
Traffic Control ◽  
San Antonio ◽  
Binary Logistic Regression ◽  
Crash Severity ◽  
Binary Logistic Regression Model ◽  
Crash Frequency ◽  
Crash Rates ◽  
Traffic Control System ◽  
The City

Intersections are high-risk locations on roadways and often experience high incidence of crashes. Better understanding of the factors contributing to crashes and deaths at intersections is crucial. This study analyzed the factors related to crash incidence and crash severity at intersections in San Antonio for crashes from 2013 to 2017 and identified hotspot locations based on crash frequency and crash rates. Binary logistic regression model was considered for the analysis using crash severity as the response variable. Factors found to be significantly associated with the severity of intersection crashes include age of driver, day of the week, month, road alignment, and traffic control system. The crashes occurred predominantly in the highdensity center of the city (downtown area). Overall, the identification of risk factors and their impact on crash severity would be helpful for road safety policymakers to develop proactive mitigation plans to reduce the frequency and severity of intersection crashes.

scholarly journals Control Strategy Optimization for Two-Lane Highway Lane-Closure Work Zones

2019 ◽  
Vol 11 (17) ◽  
pp. 4567 ◽  
Author(s):  
Hua ◽  
Wang ◽  
Yu ◽  
Zhu ◽  
Wang
Keyword(s):  
Control Strategy ◽  
Traffic Control ◽  
Queue Length ◽  
Control Strategies ◽  
Good Alternative ◽  
Management Control ◽  
Work Zone ◽  
Delay Model ◽  
Work Zones ◽  
Two Phase

Traffic control is very important for two-lane highway lane-closure work zone traffic management. Control of the open lane’s right of way is very similar to that of a two-phase signalized intersection. Thus, four control strategies including flagger control, pre-timed control proposed by Schonfeld, pre-timed control proposed by Webster, and actuated control are employed for possible use at work zones. Two primary methodologies, the mathematical delay model adopted from signalized intersections, and the simulation model calibrated with field data, are proposed. The simulation and mathematical results show that control strategies for two one-way road intersections could be used for two-lane highway lane-closure work zones. Flagger control after gap-out distance optimization prevails over all the other control strategies in terms of stopped delay, queue length, and throughput, under low or high volumes. Actuated control could be a good alternative for work zone areas due to its small queue length and large vehicle throughput under moderate volume conditions. Our findings may help to optimize the work-zone control strategy and improve operational efficiency at two-lane highway lane-closure work zones.

Study on Control Design of Interchange Entrance Congestion Zone

2013 ◽  
Vol 361-363 ◽  
pp. 2270-2275
Author(s):  
Xian Guang Wang ◽  
Xiao Nian Sun
Keyword(s):  
Traffic Safety ◽  
Control Strategy ◽  
Traffic Control ◽  
High Speed ◽  
Road Network ◽  
Control Strategies ◽  
Operational Reliability ◽  
Traffic Demand ◽  
Traffic Characteristics ◽  
Overall Reliability

Interchange entrance area is the key point which affects the overall operational reliability of an Interchange. In order to alleviate the crowded ramp merging area, improve the overall reliability of the interchange and improve traffic safety, when traffic demand increases to a certain extent, traffic control strategies should be used. According of the characteristics of the interchange ramp entrance area, the control strategy of interchange and the mainline which affect the reliability of high-speed road network most has been researched. Analyzing the geometric and traffic characteristics of the ramp merging area, different control strategies on the ramp and the mainline are proposed, that is ramp access control strategy and the main line lane running constraint strategy.

scholarly journals Safety Evaluation of Freeway Speed-Change Lanes Based on Crashes and Simulated Conflicts

2021 ◽  
Author(s):  
Lei Qin
Keyword(s):  
Traffic Control ◽  
Goodness Of Fit ◽  
Linear Models ◽  
Negative Binomial ◽  
Prediction Models ◽  
Control Strategies ◽  
Safety Evaluation ◽  
Safety Performance ◽  
Assessment Model ◽  
Crash Prediction Models

To facilitate the evaluation of the safety performance of freeway merge, diverge, and weave areas, conventional crash-based Safety Performance Functions (SPFs) were developed using generalized linear models (GLM) with a negative binomial (NB) error structure. However, crash-based SPFs may not take into account all factors that contribute to the crashes. The use of simulated conflicts as a surrogate safety measure to predict crashes can address this issue and provide recommendations for the designs and traffic control strategies. This approach was explored by using Surrogate Safety Assessment Model (SSAM) and VISSIM software to generate and analyze conflicts for merge areas on Ontario freeways. Crash-conflict integrated SPFs with different Time to Collision (TTC) thresholds were then developed and compared. Their predictive capabilities were also evaluated. To complement this analysis, the transferability of US crash prediction models to Ontario data was evaluated and the goodness-of-fit of these models was explored.

scholarly journals Traffic Control Models Based on Cellular Automata for At-Grade Intersections in Autonomous Vehicle Environment

2017 ◽  
Vol 2017 ◽  
pp. 1-6 ◽  
Author(s):  
Wei Wu ◽  
Yang Liu ◽  
Yue Xu ◽  
Quanlun Wei ◽  
Yi Zhang
Keyword(s):  
Cellular Automata ◽  
Traffic Safety ◽  
Traffic Control ◽  
Control Strategies ◽  
Autonomous Vehicle ◽  
Traffic Flows ◽  
Traffic Efficiency ◽  
Cooperative Driving ◽  
Proposed Model ◽  
Vehicle Platoon

Autonomous vehicle is able to facilitate road safety and traffic efficiency and has become a promising trend of future development. With a focus on highways, existing literatures studied the feasibility of autonomous vehicle in continuous traffic flows and the controllability of cooperative driving. However, rare efforts have been made to investigate the traffic control strategies in autonomous vehicle environment on urban roads, especially in urban intersections. In autonomous vehicle environment, it is possible to achieve cooperative driving with V2V and V2I wireless communication. Without signal control, conflicted traffic flows could pass intersections through mutual cooperative, which is a remarkable improvement to existing traffic control methods. This paper established a cellular automata model with greedy algorithm for the traffic control of intersections in autonomous vehicle environment, with autonomous vehicle platoon as the optimization object. NetLogo multiagent simulation platform model was employed to simulate the proposed model. The simulation results are compared with the traffic control programs in conventional Synchro optimization. The findings suggest that, on the premises of ensuring traffic safety, the control strategy of the proposed model significantly reduces average delays and number of stops as well as increasing traffic capacity.

scholarly journals Driving Safety Assurance Method in Work Zone Crossovers of Highway Reconstruction and Expansion Project

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Lu Lv ◽  
Yanting Sheng ◽  
Cancan Song ◽  
Yongqing Li ◽  
Zhongyin Guo
Keyword(s):  
Traffic Safety ◽  
Traffic Control ◽  
Simulation Experiment ◽  
Work Zone ◽  
Driving Simulation ◽  
Driving Safety ◽  
Transportation Safety ◽  
Control Zone ◽  
Median Opening ◽  
Median Width

Work zone crossover is an important area in highway reconstruction and expansion projects because it profoundly impacts the traffic safety and efficiency of the construction sites. This research sets the different median opening widths in the driving simulation experiment, collects the vehicle control signal parameters during entrance by-pass and exit by-pass, and analyzes the driving characteristics in these sections. Comparison of the driving features between the simulation experiment and the actual driving under the same median width has been also made. We should set the median width separately because the results show that driving behaviors significantly differ between entrance by-pass and exit by-pass. When the median opening width is 70 m, the driving simulation experiment and actual driving characteristics are quite different. However, both show that driving factors of the entrance and exit by-pass are not the same. When there are two lanes in the traffic control zone and the speed limit is 60 km/h, we should set the median width at 90 m to ensure transportation safety.

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