Honestly, I'm lucky if I have a pair of gloves on me these days... My perspective is that of a full time paramedic with a 50 mile commute every day.
A standard first aid kit would no doubt be useful for the everyday small cuts and abrasions that occur. For more traumatic incidents such as wrecks on the highways, I would stock gloves and hemorrhage control items in the kit. Think TQ, trauma dressings, gauze bandages, and so forth. An emergency space blanket or wool blanket would be extremely useful, especially if you travel remote roads in the current weather we've been having in the NE. Preventing blood loss and hypothermia are key in preventing the traumatic triad of death (hypothermia, acidosis, and coagulopathy). If you want to get really fancy, I suppose you could stock a NPA and C-Collar, although traumatic spinal care is a rapidly changing practice these days. Perhaps some splints? Maybe a set of trauma shears or Leatherman Raptor if you're so inclined...
Regarding wrecks on the roads, being a good witness and collecting pertinent information for responding fire and EMS personnel is helpful. How many vehicles, how many patients, etc. Maybe a small notebook and pen for such purposes?
Fundamentally, keep it simple. It's easy to go way overboard on such things, but specific circumstances are key to the equation. What is your level of training? To a certain extent, tailor the kit to your knowledge and skill level...