So what are the different types of running surfaces and which are better to run on? Actually there are quite a few. Some are better to run on than others, but unless you're a multi-millionaire and have your own state-of-the-art track, you're probably like me and forced to run on one or more of the following types of surfaces.
Dirt or small gravel trails are great for running and are much easier on the body. Trails, however, often contain obstacles—fallen branches, unlevel surfaces, tree roots—that can cause trips or falls, so run cautiously. The first time I ran on a trail, I fell flat on my face in the first mile. Every runner gets initiated on the trail by falling at some point, but, as long as you're tuned-in and watching where you're going, it can be a great way to add variety to your weekly runs.
Grass

This is a great surface to run on because it's softer and much easier on your joints. Be sure to run in short grass not long. You may want to scope out the area before running, making sure there are no hidden holes or divots.
Tracks can be constructed using a variety of surfaces from dirt, to asphalt, to state-of-the-art Tartan Tracks made of all-weather synthetic polyurethane. Tracks are good because they are flat and some such as a Tartan Track will provide some cushion. Tracks are also great if you need to gauge your pace for specific distances such as during an interval workout.
Treadmills can be very boring, but that have an upside—they're cushioned, flat, safe (as long as you're paying attention and not checking out the hot guy/gal beside you), and great when weather or heat doesn't permit outside running. The down side is that they don't give you a true sense of outdoor running. You can regulate the percent of incline to better mimic outside running, but treadmill running tends not to strengthen the muscles that help with balance and coordination. So, if you do a lot of treadmill running, be cautious when you head outdoors. If you're a treadmill runner, add some strength training to help with balance and coordination.
Often streets and greenways are paved using asphalt. It's definitely a hard surface, but not as hard as concrete. Many experts suggest running no more than 2/3 of your mileage on asphalt.
Typically sidewalks are made of concrete. This is probably the hardest surface and most unforgiving surface you can run on. If you have a choice, avoid running on concrete. Many reoccurring injuries can be traced back to running consistently on concrete.
Slants can occur no matter what the surface is made of. Running on a slanted surface is fine for short distances, but consistently running over long stretches of slanted surface can cause a variety of biomechanical problems and injuries such as iliotibial band syndrome (ITBS). Runners and cyclists often fall victim to ITBS which is characterized by sharp or burning pain on the outside of the knee, thigh, or butt.
So, when you can, find some routes that provide a little cushion and give your body a break from the pounding of the pavement.