Catching a taxi in the city is a fairly haphazard affair. You have to get the cab driver’s attention, make sure they take the payment method you want to use (e.g. credit card), and then verify that your trip isn’t too short or too long for where they’re willing to travel. To streamline this process, many airports and other high-traffic venues require all the taxis to wait in an orderly line, and also require that they accept credit cards and abide by other standard terms.

In theory, this makes things easier for passengers. But there’s a downside as well. You see, the orderly line means that you always have to take the first cab in the line. Even if you approach a cab that is second or third, they’ll tell you to get into the first taxi instead. First in, first out seems fair to the drivers, since nobody can hustle their way into more rides. However, it also takes choice away from the customer.

How does this relate to the environment? In my experience, newer taxis are either small, energy-efficient hybrids, or large and gas-hungry minivans. And if a minivan is the first one in the line, you’re forced to ride in there, even if you’re traveling alone or with just one other person. Since big parties would have to wait for a minivan taxi anyway, this situation means that every small party traveling in a minivan uses more gas than necessary.

To correct the imbalance, they should split the taxi lines into two sections: one for small parties and one for larger ones. Or, just let smaller parties choose the first smaller vehicle in the line — or opt for a hybrid. With this approach, consumers get more choice, less gas is wasted, and the original benefits of the taxi line are still preserved.