1) Studies concerning traffic flow and traffic safety,
2) Assessment of the state of the environment and
3) Studies concerning maintenance strategies
The Project developed and evaluated nine different future scenarios, representing permutations of three different uses of studded tyres and three different salting alternatives. The alternative salting regimes were: full salting (120,000 tons per annum), 50 % reduced salting and 80 % reduced salting. The alternative usage of studded tyres was the baseline usage, i.e. 95 % passenger cars fitted with studded tyres, 50 % usage and less than 20 % usage.
The baseline situation, i.e. 120,000 tons salt used per annum and 95 % of passenger cars fitted with studded tyres, was representative of the actual practice at the commencement of the project in 1992. Since then, the total salting of roads per year has been reduced to 80,000 tons and light-weight studs that are less abrasive to pavements are now used on new winter tyres.
In the socio-economic calculations it was assumed that all the studded tyres are fitted with light-weight studs (weight 1,1 g). Also, efforts were made to take into account all the effects as broadly and comprehensively as possible. The calculations include the costs of the road authority, the road users, the society as a whole and the environment. Cost assessments are based on the costs of preventing harmful effects, the established practice (e.g. accident costs) or, in the absence of these, the best estimates of relevant experts.
The changes of socio-economic costs compared to the baseline situation are presented in Figure 1.
None of the examined scenarios was more favourable than the baseline situation. When searching for the socio-economic optimum, the accident costs become the most important factor. The accident costs strongly support retention of the baseline situation, i.e. the use of salt and studded tyres should be continued in spite of their drawbacks. Studded tyres provide added safety, especially for uncertain drivers in variable road conditions. Similarly, salting evens out variations in road conditions and provides an opportunity to travel safely and smoothly even in the winter.
The method of calculation used in this study has provided simplified answers to complex questions. All of the values were difficult to express in monetary terms. Those intending to utilize these findings should also familiarize themselves with more detailed studies, which will provide a more comprehensive view of the complexities of the field. There are articles on some of the most interesting studies of the Research Project presented on next pages of this issue.
An English overall summary report on the Project will be finalized in late 1995. Also environmental questions and studies related to this Project will be more precisely and thoroughly presented in articles in the next issue of FinnContact .
For further information, please contact the project coordinator:
ANNE LEPPÄNEN
Finnish National Road Administration
Traffic Services
P.O. Box 33
00521 Helsinki, FINLAND
Tel. int.+358 0 1487 2411,
Fax int.+358 0 1487 2662
