Duke provides free bus transportation all over the east, west and central campuses, the medical center and even a "Robertson Scholar" route to UNC's Chapel Hill campus. There are also a Durham Area Transity Authority and Triangle Transit Authority that provide inexpensive transportation around the city (in 2004, a DATA monthly pass costs $36 and a TTA pass costs $48 -- a one-time pass for TTA costs $1.50 for all routes).
If you need information about getting a ride to or from campus, please see the university's Safe Ride services (above link). The goal of Safe Ride is to provide safe transportation when you are alone at night. They will not duplicate existing bus service, but will provide safe transportation anywhere else within their range (see the map on their web site). Safe ride is not to be used solely for your personal convenience, and they may turn you down if you are using it for transportation to parties. When the driver arrives he or she will wait only two minutes before leaving to pick other people up. You will need to present your Duke ID to the Safe Ride driver.
The following information for people who like to ride a bike to campus was compiled based on input from students who use a bike as primary means of getting to campus
The roads around the Gardens and the Golf Course paths are magnificent and beautiful. No biking *in* the Gardens please. Highway 751 is also a very bikeable road, just keep an eye on traffic coming from behind. If you head north of campus on Morreene you'll quickly find peaceful roads in good neighborhoods that give way to a bit of forest and country.
Most Durham drivers are very accomodating to bikers, in that they will pass you with plenty of room and/or slow down and follow you until you can get out of the way.
In short, the immediate area is beautiful and forested, there's fresh air, and if you know what directions to go, you can bike many miles off into countryside without being bothered much. Especially on Sundays!
In other areas, like towards 9th street or northerly far down LaSalle / Hillsborough road, or any area that looks "like a town" the roads away from the university are simply too narrow, busy, and treacherous. Sidewalks cannot be relied upon because they sometimes end abruptly.
If you are on East or West campus, or living in an apartment a block or two away, then it is pretty safe to bike at night -- traffic is minimal and criminals usually avoid fast-moving people.
Get a U Lock. All others are inadequate.
Whole Foods (on Broad Street -- one block east of Ninth Street) is situated next to a bike shop the provides free air for tires.
Watch out for mud / nasty nasty sidewalks that have turned to sludge.
Many buildings don't have adequate bike hookups. But enforcement on campus is lax and you can hitch the bike to a sign or a rail and nobody will really care.
Get a blinking-light or two.
Simply, don't bike around the general Durham area. Just near Duke. Chapel Hill is A-OK biking. In fact, there is a local contingent of Critical Mass that meets up in Chapel Hill on a regular basis, and if you know what Critical Mass is, you'll know you can find lots of friends there.
It is also possible to bike from Durham to Chapel Hill but I've not tried this yet, and don't do it at night.