Vehicle Speed Characteristics in States with Uniform and Differential Speed Limit Policies

Russo, Brendan J.; Rista, Emira; Savolainen, Peter T.; Gates, Timothy J.; Frazier, Sterling

doi:10.3141/2492-01

Cited by 12 publications

(7 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is difficult to determine what the causes are for this behavior, though potential explanations may include greater risk aversion among this group or lower levels of comfort under higher stress driving environments. This finding generally aligns with previous results (18,20,22).…”

Section: Figure 4 Plot Of Parameter Estimates For Speed Quantiles For Heavy Vehiclessupporting

confidence: 94%

“…Although speed limit increases generally increase operating speeds, the exact relationship is not straight-forward and several studies demonstrate considerable variability in the magnitude of speed increases after speed limits are changed (16,17). Earlier research has shown drivers' speed selection to be impacted by not only the posted speed limit, but also by roadway and roadside characteristics, as well as traffic volumes (18)(19)(20)(21)(22). Design speed, pavement conditions, and weather are some of the other factors that directly impact drivers' speed selection while differences are also observed across vehicle types and among driver with different socio-economic characteristics (22,23).…”

Section: Introductionmentioning

confidence: 99%

“…Additional studies have investigated the relationship between roadway geometry and operating speeds, particularly on horizontal curves. The majority of these studies have also focused on freeways (16)(17)(18)(19)(20), though a few recent studies have examined speeds on rural two-lane highways (21,22). The research literature shows that increases in speed limits significantly affect speeds on two-lane roads, but the results are highly dependent on contextual factors (24).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Mahmud

Gupta

Safaei

et al. 2021

Transportation Research Record: Journal of the Transportation R

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Figure 4 Plot Of Parameter Estimates For Speed Quantiles For Heavy Vehiclessupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Mahmud

Gupta

Safaei

et al. 2021

Transportation Research Record: Journal of the Transportation R

Self Cite

View full text Add to dashboard Cite

show abstract

“…Similarly to Johnson and Pawar, they found that speeds varied more at locations with lower posted limits. Russo et al, along with other researchers, also found that speeds varied more for all vehicles on freeways with DSL, although almost as much variation was evident on urban freeways with USL of 55 mph (Russo, Rista, Savolainen, Gates, & Frazier, 2015).…”

Section: Differential Speed Limits (Dsl)mentioning

confidence: 78%

Predicting the Impact of Changing Speed Limits on Traffic Safety and Mobility on Indiana Freeways

Tarko¹,

Pineda-Mendez²,

Guo³

2019

View full text Add to dashboard Cite

After repeal of the National Maximum Speed Limit Law, states were allowed to set individual speed limits on their interstate roads. Several states opted for a uniform speed limit while others implemented differential speed limits. The current speed limit on Indiana rural freeways limits speed of passenger cars to 70 mph and restricts to 65 mph speed of vehicles with a gross weight of 26,000 pounds or more. Indiana's speed limit on urban freeways is mostly 55 mph, but varies from 50 mph on certain downtown sections to 65 mph on some suburban sections. Previous studies comparing uniform and differential speed limit settings as to safety and mobility produced inconclusive or conflicting results. This study evaluates the safety and mobility effects of alternative speed limit scenarios on Indiana interstate freeways. Differences in travel time, vehicle operation, and traffic safety were used to compare the speed-limit scenarios. The effect of speed limit was evaluated in hourly periods. The traffic conditions in these periods were classified as uncongested, intermediate, and congested and the speed limit effects were analyzed in relation to these conditions. Rural and urban freeways were analyzed separately and distinct speed models were developed for cars and trucks. Safety was estimated by probability of crash and the conditional probability of crash injury severity. Speed limit was found to affect mobility and safety mostly in non-congested traffic conditions, while no significant effects were found in congested conditions. A limited effect was detected in intermediate traffic conditions on rural freeways. Results indicate that replacing the differential 70/65 mph speed limit on Indiana rural roads with the uniform speed limit of 70 mph may be beneficial for both safety and mobility. Increasing speed limits on urban interstates is confirmed to be beneficial for mobility but detrimental to safety.

show abstract

“…Moreover, two-way eight-lane highway is often accompanied with speed control or lane control measures, such as the differentiated per-lane speed limit (DPLSL) policy. DPLSL is a speed control measure frequently used in countries like China and Thailand out of concern for traffic safety and it is widely discussed in the literature (5)(6)(7). Under the DPLSL policy, the maximum speed limit and the minimum speed limit in each lane can be different, which influences drivers' lane changing behavior and makes the traffic flow on two-way eight-lane highways exhibit more complex features.…”

mentioning

confidence: 99%

Impact of Cooperative Adaptive Cruise Control on a Multilane Highway under a Differentiated Per-Lane Speed Limit Policy

Guo

et al. 2021

Transportation Research Record: Journal of the Transportation R

View full text Add to dashboard Cite

Cooperative adaptive cruise control (CACC) has drawn wide attention in recent years for its potential throughput benefit, as it is a promising intermediate technology to the highly connected and automated vehicles. The impact of CACC on multilane highways has been the subject of several studies, but they assumed traffic under a uniform speed limit. Recent research has revealed that traffic performs differently under a differentiated per-lane speed limit (DPLSL) policy with heavy vehicle (HV) restricted lanes. Whether the benefits of CACC still remain under a DPLSL policy has not been explored. This study developed cellular automaton models to incorporate CACC-equipped and non-equipped vehicles (i.e., passenger cars, HVs) on a two-way eight-lane highway with a DPLSL. Results shown throughputs by lane increase up to 78.5% as the CACC car market penetration rate (MPR) rises. Such increases became sharper (i.e., ≥10%) for inner lanes (i.e., HV restricted lanes) and outer lanes after reaching a 40% and a 60% CACC car MPR, separately. Moreover, HVs induced a 1.5% to 15.7% throughput reduction across lanes even under higher CACC car MPRs (i.e., 60%, 80%). This DPLSL policy may cause the lanes to experience a throughput penalty when they are adjacent to lanes with a different speed limit as the MPR of CACC cars rises. Lastly, in traffic with a 60% CACC car MPR, increases are brought further by considering 10% of HV with CACC, especially on those HV non-restricted lanes. The study is helpful for policy makers to further prepare for the prevalence of CACC in the forthcoming years.

show abstract

Vehicle Speed Characteristics in States with Uniform and Differential Speed Limit Policies

Cited by 12 publications

References 9 publications

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

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

Predicting the Impact of Changing Speed Limits on Traffic Safety and Mobility on Indiana Freeways

Impact of Cooperative Adaptive Cruise Control on a Multilane Highway under a Differentiated Per-Lane Speed Limit Policy

Contact Info

Product

Resources

About