Using compressed natural gas to fuel new buses in the city’s T system may or may not make sense, but now, before the city forks out the money for three new buses, is the time to find out what’s best for Lawrence.

At a recent meeting, Lawrence city commissioners wisely put off a decision to purchase three new diesel and diesel/electric hybrid buses for the city’s fleet to give city transit leaders an opportunity to look again at the possible cost advantages of compressed natural gas buses. Transit officials looked at — and rejected — this option four years ago, but, since then, natural gas prices have plummeted, making a possible switch worth a second look.

Earlier this month, the U.S. Energy Information Agency reported the average price of diesel fuel nationally was about $3.90 per gallon. By comparison, the price of compressed natural gas averaged about $2.10 per gasoline-gallon-equivalent and dropped as low as $1 per gallon-equivalent in some parts of the country.

If the price of compressed natural gas remains that low, converting the city’s bus fleet would seem like a no-brainer, but other factors need to be considered. The low cost of natural gas is fueled by a sharp increase in recovering natural gas using fracking technology, and, as Mayor Mike Dever pointed out, there are no guarantees the fracking industry will continue to deliver natural gas at such low prices. In the meantime, the city would incur considerable expense not only to buy new buses but also to build a new quick-fill compressed natural gas fueling station, at a cost of up to $2 million, to serve the buses.

Because of the drop in prices, the use of compressed natural gas to fuel both private and public vehicles has gained considerable interest and support. Commissioners are doing the right thing by looking into the possibility, but given the upfront investment that would be required, they also are right to be cautious in deciding whether now is the right time for the T to make that switch.