Is electrifying roads different from electrifying railroads? Yes, the greatest difference is probably that whereas the road is public, the railroad is not, and that all traffic on the railroad is guided along the tracks, which does not apply to road traffic. These differences need to be taken into consideration in connection with the electrification of roads. The electrical installation needs to be protected from vehicles which drive off the roadway. Additional study is needed of what the consequences will be if a vehicle tears down the overhead line or if the overhead line penetrates the space reserved for traffic (the free space). What are suitable measures for reducing, for example, the direct risk that a vehicle will get caught in the torn-down overhead line? What is an acceptable time period for restoration of the electrical installation after it is torn down and blocks, in whole or in part, the road traffic? The answers to these questions affect the design of the installation.
Electrification of parts of the road network means designing vehicles so that they are capable of moving both along stretches of the road which are electrified and stretches of the road which are not. This is an advantage from the point of view of road electrification as road sections which are technologically difficult (expensive) then do not need to be electrified. Examples of such places are road intersections and traffic circles (roundabouts). Other obstacles can be viaducts or tunnels where overhead lines should be installed without infringing on the road’s loading gauge. Building an overhead line system in an urban environment, which presumably also exists, naturally poses a greater technological and financial challenge than electrifying a main road. The question is what would be a comprehensive optimum solution. And this is where vehicle design becomes an important aspect. Vehicles need more output (tractive force / speed) on a main road than in an urban environment and the same can apply to power. Road electrification should probably concentrate on main roads and major routes in urban environments.