The True Operating Costs Between Bus and Light Rail

Bus vs. Light Rail: Which Is Cheaper to Operate?

Light Rail train in station
(Gary Conner/Photolibrary/Getty Images)

One of the neverending arguments in the battle between buses (especially bus rapid transit) and light rail is which costs more. From the perspective of capital costs, it is clear that light rail costs more to build than bus rapid transit. This is due to the need for tracks, the electric catenary, electrical substations and other infrastructure that buses do not need. In addition, light rail lines often need their own garages, while bus rapid transit lines can store their buses at existing bus depots.

Operating Costs

In terms of operating costs, it is often argued that light rail is cheaper to operate than buses because the capacity of light rail is so much greater than buses. This allows for fewer light rail trains than buses that are operated along a corridor for the same number of passengers. One light rail train consisting of three 60-feet cars can carry as many people as four and one-half standard buses. Assuming passenger load remains constant, a light rail train that has three cars operating every 10 minutes would need to be replaced by standard buses operating almost every two minutes. In other words, six light rail trains per hour are equal to 27.5 standard buses per hour. If there is enough demand along a corridor to operate buses every two minutes, then a light rail train would have lower operating costs than buses.

How Often Do Light Rail Lines Operate?

Unfortunately, with few exceptions, American cities do not have bus corridors that have sufficient demand to operate buses every two minutes.

Instead, cities are choosing to operate their light rail lines as often or more often than existing bus service. Replacing a bus operating every 15 minutes with a two-car light rail train operating every 15 minutes is the equivalent of increasing corridor capacity by 300 percent. A two-car light rail train is the equivalent of three standard buses.

While ridership is likely to increase due to the introduction of trains, it is unlikely to increase by 300 percent.

As the table below shows, it is much more expensive, on average, to move one light rail vehicle than to move one bus. The table shows operating costs per hour for one bus and one light rail vehicle for 15 American cities that have both bus and light rail lines. The data is from the National Transit Database website and it shows that it costs almost twice as much, on average, to move one light rail vehicle per hour versus one bus. The data demonstrates that the cost is $233 per hour for one light rail vehicle versus $122 per hour for one bus.

The table shows a much wider range in the cost of operating light rail vehicles ($124.01 - $451.33 per hour) than buses ($84.61 - $163.96).

Why Does Light Rail Cost More?

There are several reasons why it costs more to operate one light rail vehicle versus one bus. There is the cost of maintaining the track right of way and associated switches and signaling. Second, there is the cost of maintaining the light rail stations and associated parking lots. This includes the cost of employing ticket collectors, security personnel and maintenance workers.

Finally, in certain cases, the cost of electricity to operate the trains may be greater than the cost of fuel for buses. This is a trend that is likely to continue in the future. One major Southern California transit agency reported an almost 500 percent increase in operating costs per mile when they replaced natural gas buses with electric buses.

Overall, it is more expensive to operate one light rail vehicle than one bus. Because of this fact, cost-effective use of light rail requires a large passenger demand. This is a demand that only exists in a few American cities, most of which already have extensive rapid transit systems. 

Light Rail Versus Bus Costs for Fifteen American Cities With Both (Source NTD)

Light Rail vs Bus
CityBus CostLight Rail Cost
Salt Lake$118.24$124.01
Los Angeles$127.28$391.43
Portland, OR$134.39$187.55
San Diego$84.61$137.67