Effects of desired speeds for queuing and delay on single-lane road segments

Publisher's full text
Mats Wiklund
Arne Carlsson

To improve road safety on parts of the road network carrying low traffic volumes, road designs are proposed including single-lane road segments and periodic overtaking lanes. These roads have been proven to contribute to substantial benefits in terms of road safety. However, overtaking of slower vehicles is only possible on segments including an overtaking lane and not on the single-lane road segments. Driver and vehicle heterogeneity resulting in differences in desired speeds are consequently decisive for the traffic performance. Sufficient quality of service is relying on an appropriate design and distribution of single-lane segments and overtaking lanes. In this paper, we study the effect of the desired speed distribution on traffic performance on single-lane road segments. Expressions are derived for the travel time, delay and percent time spent following. The derived expressions link the desired speed distribution, the single-lane segment length and the traffic flow to the resulting traffic performance. The results are verified through comparison with measures based on microscopic traffic simulation. The conclusion is that there is a good agreement between derived measures and simulation results. The derived measures should therefore not only be of theoretical interest, but also of practical use to estimate traffic performance on single-lane road segments.

MEET US


25-26
Apr

Cost Benefit Analysis (CBA) workshop in Stockholm

An open seminar and workshop in Stockholm will be held on 25-26 April 2018. The workshop deals with the use of CBA as a basis for decision-making in the public sector. The workshop is organized by, among others, Professor Jan-Eric Nilsson, VTI.

LATEST NEWS


2018-02-19

Modal shift for an environmental lift?

Investigations in Sweden and other countries suggest a shift of goods transport from road to rail and waterborne transport to reach environmental and climate objectives. VTI is leading a new project to investigate how the modal shift can contribute and what...


2018-02-13

Automation and digitalisation are making rail competitive

Road transport is developing rapidly and its productivity has increased sharply. Rail transport, however, has not developed at the same rate. Automation and digitalisation are essential if rail freight in Europe is to survive.


2018-02-08

New research is creating a driverless logistics chain

The research project Born to Drive has come up with a system that allows new cars to move, without a driver, from the production line out to the parking area prior to being transported elsewhere. The vision is to automate the entire logistics chain from...


2018-02-05

VTI testing automation in EU project

VTI is leading a series of tests in a major EU project on automated driving. The first driving tests were carried out n a test track in Slovenia in December. The project will focus in part on acceptance among different groups in society, in part on...


2018-02-02

Freight transportation on road and rail analysed

Freight transport accounts for a large proportion of the emissions, noise and congestion produced by road traffic. Transporting freight in larger but fewer lorries could reduce the problem. At the same time it might entail freight being diverted from more...


2017-11-30

Millions for research into maritime transport and the environment

Maritime transport is a major source of emissions of harmful air pollutants and carbon dioxide. In a new project, a research team from the Swedish National Road and Transport Research Institute (VTI) and the University of Gothenburg has received SEK 6.4...