I have been using a Bell LED flashing taillight from Wal-Mart both in city traffic and on rural roads. A friend saw me riding and even came up behind me in his vehicle one night without knowing who the cyclist was. He said I was visible from half of a mile away. If find cars generally go into the left lane to give me plenty of room. The Bell unit costs less than $9 and has six or seven modes with different light patterns. It runs a long, long time on 2 AAA batteries.