Author: Xin SunPublisher:
ISBN:
Category :
Languages : en
Pages : 206
Book Description
Determining the Safety Effects of Differential Speed Limits on Rural Interstate Highways Using Empirical Bayes Method
Author: Xin SunSafety Effects of Differential Speed Limits on Rural Interstate Highways
Author: Publisher:
ISBN:
Category : Roads
Languages : en
Pages : 89
Book Description
"To compare the safety effects of a uniform speed limit (USL) for all vehicles as opposed to a differential speed limit (DSL) for cars and heavy trucks, detailed crash data, speed monitoring data, and traffic volumes were sought for rural interstate highways in 17 States for the period 1991 to 2000. Conventional statistical tests (analysis of variance, Tukey's test, and Dunnett's test) were used to study speed and crash rate changes in the four policy groups. A modified empirical Bayes formation was used to evaluate crash frequency changes without presuming a constant relationship between crashes and traffic volume"--Technical report documentation page.
Safety Impacts of Different Speed Limits on Cars and Trucks
Author: David L. HarkeyPublisher:
ISBN:
Category : Speed limits
Languages : en
Pages : 78
Book Description
The objectives of this study were to determine whether differential or uniform speed limits are more beneficial to transportation safety and traffic operations on Interstate highways. The approach to achieving this objective was to examine speed and accident data from States employing both types of limits. Speed data were collected in 12 States at rural and urban locations representing all speed limits currently established on the Interstate highway system for cars/trucks, i.e., 55/55 mi/h (89/89 km/h), 65/55 mi/h (105/89 km/h), 65/60 mi/h (105/97 km/h), and 65/65 mi/h (105/105 km/h). Accident data were obtained from nine States which were geographically distributed across the country and representative of all rural Interstate speed limits currently established. For the speed data collected, a number of measures of effectiveness (MOEs) were examined including mean speed, speed variance, compliance, and speed distribution measures. For the accident data collected, types of crashes were examined (e.g., rear-end) along with vehicle type involvement (e.g., car-into-truck) and crash severity. This final report summarizes the effects of uniform and differential speed limits on transportation safety and traffic operations as determined by the examination of speed and accident data.
The Safety Impacts of Differential Speed Limits on Rural Interstate Highways
Author: Interim Report on the Safety Consequences of Raising the Speed Limit on Rural Interstate Highways
Author: Highway Safety and the 65 MPH Maximum Speed Limit
Author: Patrick S. McCarthyPublisher:
ISBN:
Category : Speed limits
Languages : en
Pages : 72
Book Description
Effects of the 55 Mph Speed Limit
Author: American Association of State Highway and Transportation Officials. Operating Subcommittee on Traffic EngineeringPublisher:
ISBN:
Category : Speed limits
Languages : en
Pages : 66
Book Description
Safety Comparison of Roadway Design Elements on Urban Collectors with Access
Author: Highway Safety
Author: United States. General Accounting OfficePublisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 36
Book Description
Technical Assistance Report 17-01-TA-SS
Author: Haggai DavisPublisher:
ISBN:
Category : TRANSPORTATION
Languages : en
Pages : 0
Book Description
"The National Highway Traffic Safety Administration (NHTSA) reported that 37,461 people died in 2016 on US roads, marking the second year in a row that the number has increased [1]. Many transportation-related agencies have adopted a “Vision Zero” or “Towards Zero Deaths” campaign aiming to eliminate the need for that statistic. Speed can often play a role in fatalities, so setting the proper speed limit for roadways is important in saving lives. American speed limits have a complicated history over the past 50 years, which hinders researchers’ ability to look at much longer stretches of data and draw conclusions about determining the best speed limit strategy. From 1973 to 1987, the maximum speed limit was 55 MPH. After that, Congress raised the allowable limit to 65 MPH. It was not until 1995 that states had full discretion over setting an appropriate limit. Some states raised the speed limit for all vehicles equally – a uniform speed limit (USL). Others raised speeds for trucks less than that of cars – a differential speed limit (DSL). On the surface, the benefit of a DSL seems intuitive, lowering the speeds for big trucks would reduce the severity of accidents. However, it also has the effect of increasing total variance in speed which increases the number of accidents. This report aims to explore the literature published about these issues and to inform decision makers about the factors to be weighed when considering DSL versus USL. It was prepared in response to a request in the 2017 session of the Louisiana House of Representatives where the Louisiana Department of Transportation and Development (DOTD) was asked to “study the safety and operational impacts of differential speed limits on interstate highways” (House Concurrent Resolution 112). Thus, the purpose of this study is to inform the Louisiana Legislature about the documented benefits and costs of a differential speed limit for passenger cars versus larger vehicles specifically with regards to the topics of Safety, Mobility and Operations, Fuel Consumption and Emissions, and Truck Determination as outlined in HCR 112."--Introduction.