In Finland, the average implementation cost for a weather responsive roadside VSL system on a dual carriageway was estimated at 80,000€; average maintenance costs (including replacement costs) were estimated at 3,500 €/km/year.

25 March 2006

Summary Information

In Finland, approximately 350 km of roadway have been equipped with variable speed limitsmost of them are weather-controlled. This study estimated the benefits and costs of expanding the system. Three different size networks were modeled to establish parameters for the cost-effective expansion of the system. Evaluation data collected from previous studies were projected onto the models which ranged in size from 2100 to 4300 km. Each model represented a contiguous network of variable speed limit signs (LED signs) that were controlled automatically by information produced by road-weather sensing stations. The road sections belonging to each network were selected based on set traffic safety and traffic volume criteria. The speed limits displayed were determined according to a control policy formulated by the Finnish Road Administration.

The benefit-cost analysis covered a period of 20 years and assumed a two percent annual increase in traffic and a five percent decrease in personal injury accidents. Ancillary impacts on pollution and noise costs were assumed marginal and were not included in the analysis. The system costs data input into the analysis included construction and maintenance costs derived from recently built systems.

The implementation plan was designed to accommodate two types of facilities: motorways and dual carriageways (divided highways), and single carriageways (roadway with no physical separation). The following data excerpted from table 2 of the report show the combinations of technologies deployed.

Road type
Speed limit signs
Combined information and warning signs
Traffic monitoring stations
Road weather stations
Traffic monitoring cameras
Motorways and dual carriageways6 units /graded intersection if the spacing between intersections is longer than 5km speed limit repeater signs are required (4 units)One for each carriageway for each intersection spacingEvery graded intersection spacing has one traffic monitoring stationOne for every 15kmOne for each graded intersection
Single carriageways4 units /intersection if the spacing between intersections is longer than 5km speed limit repeater signs are required (2 units)One for every other intersection spacingOne for each 20kmOne for each 15kmOne for each 20km

The results of the benefit-cost analysis were favorable for deployments along highly trafficked road segments. Starting (low-end) benefit-to-cost ratios ranged from 1.1:1 to 1.9:1. Ratios increased for scenarios where higher safety benefits were assumed and control policies allowed for higher speed limits.

System Costs

Construction and annual maintenance costs were evaluated at the 2004 level. The data below excerpted from table 3 of the report estimated average implementation costs, 20 year maintenance costs, and the cost distribution for construction costs.

Road type
System implementation
(construction costs)
20 year system maintenance and
replacement costs
Construction cost distribution
Monitoring systems
(traffic and cameras)
Motorways and
dual carriageways
80,000 €/km
3,500 €/km/year
Single Carriageways
36,000 €/km
1 000 €/km/year

The estimates above show that the average cost to equip a dual carriageway was about double that of a single carriageway. Most of the construction costs were attributed to cabling.

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Country-Wide Variable Speed Limits?

Author: Schirokoff, A., P. Rama, and A. Tuomainen

Published By: Paper presented at the XIII International Road Weather Conference (SIRWEC) 2006

Source Date: 25 March 2006

System Cost

Weather-controlled VSL system on dual carriageway: 80,000€.


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Cost ID: 2008-00145