I agree with those who say higher speed roads with no shoulder or bike lane. Basically, roads that are designed with only cars in mind. I currently live in Taiwan, but lived in the Houston area most of my life. Here, everyone expects bicycles to be part of the mix on the road and generally speaking, roads in the city have lower average MPH than in the US. In Houston, many roads have no shoulders and posted speeds of 40-50 MPH. Much scarier when when people drive faster, have no patience, and insist on squeezing by where there's no room.