I think one of the main problems with drivers licenses is that people take driving as a right. By that I mean a license should not necessarily mean you should continue to drive, especially since an automobile or motorcycle can be considered a very dangerous weapon.
Yes, you do have to take a written test and a road test, and in most cases you only have to take those once in your life. This is where I have a problem with driver's licenses. Take a physician's medical license or a nurse's license to practice, they are required to renew these periodically, take continuing education classes each year, and continually prove competency. Why couldn't we have a similar process in place for driver's licenses.
My mother, who is 65+, has a valid driver's license, yet she has not driven in almost 20 years and there is no way I would get in the car if she did decide to drive. Since she last drove, there have been so many more things to consider when driving, e.g., cell phones, bike lanes, speeding cameras, HOV lanes, many many more vehicles on the road, an increase in the size of cars (the SUV phenomena), her slower reaction times, her worsening vision, etc. It maybe more of a burden to citizens, but why not require continuing driving education and driver's tests every few years in order to renew drivers' licenses?
Driving should be treated more like a privilege that is earned, rather than an innate right and then maybe we can then have safer streets.