2+1-roads with cable barriers - safety and traffic performance results

Torsten Bergh
Arne Carlsson

The objectives of this paper are to present the Swedish National Road Administration (SNRA) development program to upgrade traffic safety on existing 13 m using low cost measures, and also to summarize all important results and findings until April 2001 from opened projects as yet, totally about 200 km. There is a significant gap in traffic performance, safety,investment and maintenance costs, land requirement and intrusion between normal two-lane and four-lane cross-sections. In Sweden this gap so far hasbeen filled with a 13 m road with 3.75 m traffic lanes and 2.75 m hard shoulders. The traffic performance of these roads is quite satisfactory but there are safety problems with fatal accidents. Almost 100 people are killed and about 400 people are severely injured every year on 13 m roads due to thehuge traffic load, still being the safest two-lane road. The main problem onall two-lane roads is run-off and meeting accidents causing more than 50% ofall fatalities. The event process tends to be the same. The driver looses control for some reason and crashes against some obstacle in the roadside area or in the shape of an opposing unlucky driver. In 1998, the directorgeneral of SNRA decided on a full-scale program to improve traffic safety on six existing 13 m roads using low-cost measures, preferably within an existing right-of-way. The main alternative is the 2+1-solution with aseparating cable barrier, preferable within the existing width 13 m. This solution was estimated to have a potential to prevent some 50% of all severe link accidents. Findings so far have been judged so successful that SNRA has decided to replace the old 13 m road with the 2+1-solution on a general basis.



Shipping and the environment – research meets reality

Centre for Transport Studies (CTS) in co-operation with Ports of Stockholm invite you to the seminar Shipping and the environment – research meets reality.



Simulation of cut-in by manually driven vehicles in platooning scenarios

A study in a VTI-driving simulator has showed that a platoon will be able to handle a cut in from a manually driven car. The results of this study have recently been presented at two conferences in Japan.



The five-year anniversary of European Road Profile Users' Group (ERPUG) Forum will take place at Ramboll head quarter, Copenhagen, Denmark October 19-20, 2017.


Self-driving buses in Sweden next year?

A self-driving, fossil-free bus. This idea might become reality through a forthcoming collaborative project involving the Swedish National Road and Transport Research Institute (VTI), Linköping University and several other participants. The project group aim...


New climate-proof solutions for hard surfaces in cities

High-density road infrastructure that emphasise maximum durability and minimum maintenance create inflexible systems, which put increased stress on urban trees and lead to increased risk for flooding. Over the past five years, the ‘Climate-proof solutions for...


VTI is preparing for automated vehicles

Automation of traffic systems will lead to major changes. The European Union’s (EU) CoEXist research project began in June 2017 with the aim of preparing cities and road operators for the introduction of self-driving vehicles. The Swedish National Road and...


Vehicle Driver Monitoring: sleepiness and cognitive load

To prevent road crashes it is important to understand driver related contributing factors, which have been suggested to be the critical reason in 94 per cent of crashes. The overall aim of the project Vehicle Driver Monitoring has been to advance the...