The drive back from the city courses through the mountain for a little over a hundred miles. On the way, the highway takes drivers through one of the highest vehicular tunnels in the world which is also the highest point in the United States Interstate Highway System at 11,158 feet. If you happen to be traveling in a vehicle that exceeds thirteen and a half feet or is transporting hazardous materials you will have to take the longer steeper route through Loveland Pass. The same is true if you happen to be traveling by bicycle or walking. This route is also employed when any sort of trouble in the tunnel has caused a large backlog of motorists.