Vehicle census shows what kinds of vehicles are on our region’s roads


What kinds of cars and trucks are on our region’s roads? TPB planners are interested in understanding the current characteristics of cars, trucks and buses in our region. Knowing this information helps them more accurately forecast mobile emissions and see if our region is meeting its air quality goals.

Every few years, TPB staff compiles a list of registered vehicles from the region’s three departments of motor vehicles. Each vehicle has a unique Vehicle Identification Number (VIN). VINs are kind of like finger prints for vehicles.

Special software unlocks a wealth of information from these seemingly cryptic numbers and letters. VINs indicate vehicle types—whether it’s a car or a truck, its age, and if it runs on electricity, gas, or if it’s a hybrid. This information helps paint a picture of how these vehicles contribute to the air quality in the region.

TPB planners have analyzed VIN data on an approximate three-year cycle since 2008. The analysis covers the District of Columbia and 10 surrounding jurisdictions in Virginia and Maryland. The current analysis is based on December 2016 registration data.

Let’s look at what this latest VIN analysis shows:

The fleet has continued to grow

There are now about 4.1 million registered vehicles in our region, up from 3.89 million in 2014. Steady growth has been observed uniformly across DC, Maryland and Virginia.

The numbers of vehicles in our region has continued to grow. (TPB)

For the first time there are more newer vehicles

For the first time since 2008, the average age of the fleet has decreased. Between 2008 and 2014, vehicle owners in our region appeared to keep their cars longer. The average vehicle age grew from 8.18 years in 2008 to 9.49 years in 2014. This time, the December 2016 analysis showed an average vehicle age of 9.17 years. It will be interesting to see if this increase in people buying new vehicles will continue over the years to come or if this is one outlier.

On average the vehicles making up the region’s fleet are getting younger. This means that people are trading in older cars and trucks for newer ones. (TPB)

More light-duty trucks and SUVs

The analysis also shows that light-duty trucks, including Sport Utility Vehicles (SUVs), on our region’s roads have increased in number and in share. The share of SUVs has increased by about 2% since 2014 (from 40% to 42%). One might speculate that the increase in the share of SUVs may be the result of lower gas prices that make SUVs more affordable, as well as the fuel economy improvements of light-duty trucks in general.

One possible explanation for more light trucks and SUVs in the fleet could be lower gas prices. (TPB)

Electric cars are making gains

TPB researchers also track the trends in hybrid and electric vehicles. In this latest count, while there are more hybrid vehicles out on the roads, there has been a relative decline in hybrid vehicle purchases in recent years.

In recent years there’s been a decline in purchases of hybrid vehicles. (TPB)

This decline has been somewhat offset with an increase in purchases of electric vehicles. It’s possible that previous hybrid vehicle owners have decided to buy electric vehicles since they’re becoming more popular. However, the hybrid-to-electric switch does not fully explain the decline in the number of recent purchases of hybrids. Recent improvements in fuel economy for non-hybrids (i.e., internal combustion engine vehicles) have made those vehicles cheaper to operate as well.

Electric vehicles are becoming more popular. (TPB)

How the TPB uses this data

TPB planners conduct the VIN count every few years to be able to accurately analyze the four-year update of our long-range plan for how it will affect air quality. By looking at the make-up of the region’s vehicle fleet we can have a clearer understanding of the emissions coming from these vehicles.

Here's how we use growth forecasts for transportation planning