If you're running in the early morning or at night, even at dusk, wear white, yellow, or orange clothes. Also, make sure you have reflective gear on. Although some items (running shoes, jackets) already have reflective pieces on them, it doesn't hurt to add more. A headlamp or flashlight is also a great item for runners who do a lot of early morning or evening running.
Choose a well-lit route It might not be your favorite route to run, but the most well-lit route is your safest choice. Oncoming cars see you better, and you'll always be able to see the road and avoid potential hazards.
Always run against traffic It's easier to avoid cars if you can see them coming. Avoid busy roads and those with no shoulders or sidewalks.
Run with a Buddy There's strength and safety in numbers. If possible, try to never run alone. If you're running alone, let someone know the route you're running and approximately how long you will be out.
Carry a cell phone You'll be able to contact police immediately if something happens to you or you notice anything out of the ordinary.
Vary your routes and times Potential attackers can study runners' routines and loom in a particularly dark or isolated area. Don't make yourself an easy target.