Safety Effects of Differential Speed Limits on Rural Interstate Highways

Garber, Nicholas J; Miller, John S.; Yuan, Bo; Sun, X.

doi:10.3141/1830-08

Cited by 20 publications

(8 citation statements)

References 2 publications

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“…In 2005, Garber et al compared crash, traffic volumes, vehicles speeds, and other data for Virginia, which had transitioned from a DSL policy to a USL policy, and three other groups: (a) states that were transitioning from USL to DSL, (b) states that were maintaining USLs, and (c) states that were maintaining DSL (40). The results showed differences between passenger vehicle and truck speeds but no consistent safety differences.…”

Section: Dsls Versus Usls For Trucks and Busesmentioning

confidence: 99%

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

Russo

Rista

Savolainen

et al. 2015

Transportation Research Record: Journal of the Transportation R

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The purpose of this study was to examine the travel speed characteristics of passenger vehicles, trucks, and buses in states with different speed limit policies, primarily to ascertain the effects of differential speed limits (DSLs) versus those of uniform speed limits (USLs) for large vehicles. Spot-speed studies were conducted in the neighboring states of Indiana, Michigan, and Ohio; these studies permitted examination of speed characteristics under several speed limit settings along the same freeways. The sites included urban and rural locations, with speed limits at individual locations that varied from 55 to 70 mph. These sites included USLs and DSLs, with 5 mph differentials on rural freeways in Indiana and 10 mph differentials at rural locations in Michigan. Spot-speed data were collected at 157 freeway sites in the three states along flat, tangent segments. Regression models were estimated to ascertain differences in the mean speeds, the 85th percentile speeds, and the standard deviation in speeds across locations. The results showed passenger vehicle speeds to be quite consistent across the three states where a common 70 mph limit was in effect. Speeds varied more at locations with lower posted limits and between trucks and buses. Speeds were most consistent in Ohio at locations with higher USLs. The variability in travel speeds for all vehicles was found to be highest on freeways with DSLs, followed by urban freeways with USLs of 55 mph.

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Section: Dsls Versus Usls For Trucks and Busesmentioning

confidence: 99%

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

Russo

Rista

Savolainen

et al. 2015

Transportation Research Record: Journal of the Transportation R

View full text Add to dashboard Cite

show abstract

“…DSLs for trucks and cars are becoming a promising way to enhance highway operation and safety. Thus, in this study we focus on DSL strategy which restricts vehicles with specific size and weight, to travel at lower speeds than the rest of the traffic stream [ 42 ], as heavier vehicles require a larger stopping distance and stopping time than do passenger cars [ 43 ]. Thereby, vehicles are divided into three types based upon their capacities.…”

Section: Intelligent Advisory Speed Limit Dedication (Iasld)mentioning

confidence: 99%

Intelligent Advisory Speed Limit Dedication in Highway Using VANET

Jalooli

Shaghaghi

Jabbarpour

et al. 2014

The Scientific World Journal

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Variable speed limits (VSLs) as a mean for enhancing road traffic safety are studied for decades to modify the speed limit based on the prevailing road circumstances. In this study the pros and cons of VSL systems and their effects on traffic controlling efficiency are summarized. Despite the potential effectiveness of utilizing VSLs, we have witnessed that the effectiveness of this system is impacted by factors such as VSL control strategy used and the level of driver compliance. Hence, the proposed approach called Intelligent Advisory Speed Limit Dedication (IASLD) as the novel VSL control strategy which considers the driver compliance aims to improve the traffic flow and occupancy of vehicles in addition to amelioration of vehicle's travel times. The IASLD provides the advisory speed limit for each vehicle exclusively based on the vehicle's characteristics including the vehicle type, size, and safety capabilities as well as traffic and weather conditions. The proposed approach takes advantage of vehicular ad hoc network (VANET) to accelerate its performance, in the way that simulation results demonstrate the reduction of incident detection time up to 31.2% in comparison with traditional VSL strategy. The simulation results similarly indicate the improvement of traffic flow efficiency, occupancy, and travel time in different conditions.

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“…Wilmot and Khanal (1999) documented the effect of speed limits on vehicle speed and safety on roadways and concluded that there was no evidence of a positive impact of differential speed limits on highway safety. A report, by Garber, Miller, Yuan, and Sun (2003), compared the safety effects of differential speed limits on rural interstate highways to those with uniform speed limits. In this work it was found that changing from a uniform speed limit to a differential speed limit or vice versa had no impact on the mean speed and speed variance.…”

Section: Differential Speed Limitsmentioning

confidence: 98%

Trucker Perceptions of Lane Restriction and Differential Speed Limit Policies on Freeways

Wolshon

Ishak

Yuan

et al. 2009

Journal of Transportation Safety & Security

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To improve the efficiency and safety of traffic flow on freeways, several states have implemented truck lane restriction and differential speed limit policies. The State of Louisiana introduced such restrictions on an 18 mile elevated four lane rural segment of Interstate 10 (I-10) in response to an 11 vehicle crash in September 2003. The new control policies, implemented in 2003, have restricted trucks to the right lane only and reduced their speed limit to 55 mph. At the same time the speed limit for passenger cars was also reduced from 70 mph to 60 mph. This article summarizes the findings of a survey to assess truck drivers' perceptions and opinions of these restrictive policies. Another objective of the survey was to solicit ideas and input for other potential strategies that could be useful to the drivers. Overall, the results showed that the truckers were not in favor of the restrictions and did not feel that a significant safety benefit was being gained from these restrictions.

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Safety Effects of Differential Speed Limits on Rural Interstate Highways

Cited by 20 publications

References 2 publications

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

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

Intelligent Advisory Speed Limit Dedication in Highway Using VANET

Trucker Perceptions of Lane Restriction and Differential Speed Limit Policies on Freeways

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