Are there any figures available on gas tax revenues collected by county? Even though "all the people" are in NoVA, Richmond and Hampton Roads, do those areas generate a percentage of gas tax revenues anywhere near their percentage of the population? I'd say not, because commute distances are probably shorter, and lots of people use public transportation.
I'm not finding any, but let's approach this issue a slightly different way.
New Jersey, a state dominated by urban and suburban areas which is the most densely populated in the union, collected $535,550,000 in gas tax revenues in 2015
(source) with a 14.5 cent/gallon tax and a population of 8.96 million. This maths out to about 412 gallons of gas purchased per resident.
Wyoming, a very rural state which is the least populous in the union, collected $118,639,000 in gas tax revenues in 2015 (same source as NJ) with a 24 cent/gallon tax and a population of 582,102. This maths out to about 849 gallons of gas purchased per resident.
So yes, at a glance it would appear that the per capita contribution of rural areas to gas taxes is greater than that of urban areas, potentially by a factor of about 2. This is likely explained both by the greater distances needed to travel in rural areas and the greater tendency of people in rural areas to drive larger vehicles that are less efficient.
The variable this is not controlling for is the fact that a state with a low population that's spanned by a major transcontinental corridor is likely going to sell a greater percentage of its gas to people from out of state than a small, densely populated state is. And this would hold true on a smaller scale too - any gas station located off of I-81 in VA is going to sell more gas to non-locals than a gas station in Arlington is. The source of the revenue will not always match the contributor's residence.