37. The U.S. Interstate Highway program was discussed for more than two decades before actually being built. It does not appear that any clear alternative transport investment plan was being discussed at the time. The options were to finance the new program, or to keep the existing transportation network.<sup>32</sup> From this one could conclude that there was no alternative and an investment in the interstate highway system was unavoidable. To some extent, that was true. However, roughly at the same time, high-speed train systems were designed in Japan and, a decade later, in France (as discussed in the following box). At least at the global level it is clear that alternative transportation technologies (with low carbon emissions) were known at the time the U.S. Interstate Highway System was established. But, the alternative was an imperfect one—it was costlier per unit mile of construction, it did not handle freight transport, and it was not a dense network linking all the cities. Nonetheless, it was far more efficient in terms of energy and emissions per passenger mile in the corridors in which it operated, and there was nothing in the technology that precluded design of a denser network.

- **<mark>Box 4. Low carbon emissions in transport is linked to how electricity is generated: The case of France’s High-Speed Train Program</mark>**

<mark>38. The French high-speed train program was initiated in the late 1960s by SNCF, the French public enterprise which had monopoly over both rail infrastructure and rail transportation. The objective was to limit train ridership erosion by competing more efficiently with cars and planes over major intercity corridors, not specifically to save energy or to limit greenhouse gases emissions. The first highspeed train (TGV) prototype was natural-gas powered, but after the 1973 oil shock electrical engines were adopted. This shift was a conscious decision to limit the energy cost of running the future train. It is unclear whether it was made specifically to take advantage of the nuclear power generation program that was launched in 1974 (see box n°1). (Again, even though at the time reducing emissions was not a goal, the shift away from fossil fuel in the name of energy independence had the same</mark> effect.)<sup>33</sup> <mark>39. The first high-speed railway between Paris and Lyon was commissioned in 1974 and became operational in 1981. Travel time between the two cities—400 km apart—was reduced from 4 to 2 hours, and travel time to cities further South along the same corridor was also reduced considerably. Ex-ante and ex-post traffic surveys show that the modal share of rail increased considerably relative to both roads and aviation in the corridors with high-speed rail. For example, the share of rail on the Paris - SE corridor jumped from 44% to 61% from 1981 to 1984, while the share of road diminished (from 46% to 30%) and the share of air also eroded slightly (from 10% to 8%) (OEST, 1986). The surveys also point to a long-lasting overall increase in travel demand induced by the opening of the new line along the corridor where the TGV is built (OEST, 1986, 1987). As new high-speed railways were built, similar effects have been observed for inter-city trips up to 800 km. For example, it is</mark>

> 32 See the extensive discussion of the origins of the U.S. Highway System by Lee Mertz

> (http://www.fhwa.dot.gov/infrastructure/origin.htm).

> 33 High speeds (i.e., over 220 km/h) can be achieved only on special railtracks with, inter alia, higher curvature radiuses than regular railtracks, larger mid-track intervals, adapted bridges and tunnels, etc. Since the speed of all trains on a given railtrack cannot exceed the speed of the slowest train, high-speed railtracks are TGVs-only (in addition, slower trains are not adapted to certain physical characteristics of high-speed railtracks such as steep ramps). TGVs, on the other hand, can run on regular railtrack (albeit at lower speed), thus making high-speed railtracks an extension of the existing railtway network, and not an entirely new network. (This is no longer the case when high speed is achieved through different technologies, such as magnetic levitation.) The higher design standards are similar to the Interstate highway systems which are very different from regular highways. To support high speeds ‘on and off ramps’ have to have higher curvature radii, traffic in different directions have to be separated from each other, entrances and exits from the traffic stream are spaced much further apart, etc.

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