Can a commercial airliner be landed on a highway, e.g. Highway 405 in Los Angeles? In a famous sequence from the TV show 24, a Boeing 727 is forced to land on the 405 in Los Angeles. It is a well-known myth that the interstate highway system was set up as a series of airstrips. But would it be feasible to land a commercial airliner on the 405 highway from an aviation perspective, given that there were few if any cars on the road? (Of course, anyone who lives in LA will tell you that there is never a time of the day or night when the 405 is not busy - so this is purely theoretical.)
It's possible, assuming the section chosen has no streetlamps, signs, overpasses etc. The police can block the traffic easy enough.

However, there would be zero reason to do so. If a plane has enough control to reach the highway, and enough advance notice to find a suitable part and block the traffic then it has enough control and time to reach one of the many airports in the region. Much less fuss for all concerned, and a much better equipped crash service.

In the prairies one could set up a fighter or bomber base on a random road, but again there's no need to - there's nothing nearby that would require it, heavy bombers or commercial planes would quickly destroy a normal highway and fighters could use the many civil airstrips in the area.

In Europe the math is different - opponents are a short flight away and destroying the airbases on both sides would be a top priority in any European conflict. See "Highway strip" in the usual reference for more details.