Roads on Mars are one of the possible surface transportation infrastructures. Short roads will necessarily be build around colonies and a larger network might exist between settlements and mines, or other settlements and facilities.
Rovers, more or less by definition, do not require roads. By the same measure, as soon as roads become available, the importance of rovers will decline as they become specialized exploration vehicles, as opposed to more common surface transportation vehicles.
Road building on Mars
Ground preparation for roads on Mars should be quite simple. There is no soil on Mars, and no swamps, so the surface should be quite solid, with the exception on dunes and wind transported sand. Rock breaking equipment, combined with crushers and graders should be capable of quickly and cheaply building good quality gravel roads.
Rolling surfaces for higher speeds would probably need to be some kind of concrete, as asphalt would not be available on Mars. Ice might be used as an alternative binder, but might also be subject to rapid sublimation in summer periods. Sulfur in another possible alternative binder.
Weather and other Martian particularities
Dust accumulation from dust storms and dust devils might affect the driving surfaces somewhat. Dust plows, as used in desert countries such as the United Arab Emirates could be used to control the dust. Self driving vehicles using purely optical systems might have some difficulty in a dust storm, but radar based sensors might be added. References for sensors, embedded in the roadbed, may last a long time on Mars, due to the lack of erosion.
Erosion should be practically non existent, giving roadways on Mars a very long life. Ground loading stress from the rolling equipment should also be lower than on Earth, due to the lower gravity.
Noise from rolling vehicles will be less of a problem than on Earth. Vibration might be reduced as well, as the gravitational potential energy of a vehicle rolling on Mars will be lower than on Earth. Kinetic energy from vehicle speed will be the same on both planets, however.
Vehicles on Mars may have batteries or be methane/oxygen powered. It seems likely that all Martian vehicles will be electrical, unless methane is found in an exploitable form. And even then, the energy required to produce oxygen may make the existence of the methane rather moot. Vehicles on Mars will probably charge at solar powered charging stations, analogous the the ones presently being added to the Earth road infrastructure.
Self driving vehicles
All vehicles on Martian roads may be self driving. As there is no real weather on Mars, and the infrastructure will be new, it should be possible to incorporate self driving aids into the roadways, if necessary. This could mean that truck driving never becomes a profession on Mars. This also reduces one of the advantages of rail transportation, as self driving vehicles only require maintenance personnel and therefore do not have high personnel costs.
Roads vs railways
Practically by definition any roadbed of sufficient quality to support railway tracks will also be sufficient to carry wheeled vehicles.
Martian cities are likely to be very dense. This may favor rail over roads for intercity transportation, in particular if the rail is operating at Martian atmospheric pressure and the city distribution system is operating at breathable pressure.