JEIMY ZEPEDA was in an accident two blocks from her Connecticut home last year. One of her children was injured; her van was written off. The other driver fled the scene. His car was unregistered; he was presumed to be an illegal immigrant with no driving licence. So is Ms Zepeda. Illegals are often reluctant to call the police; they always ask for a driving licence. “Even when it isn’t your fault, just not having [a] licence makes you guilty,” says Armando, her husband.

As the Senate voted this week to allow debate on comprehensive immigration reform, several states are pondering a narrower problem. Until this year illegal immigrants could not legally drive except in New Mexico, Utah and Washington state. So they typically drive without lessons, testing or insurance.

This is dangerous: unlicensed drivers are almost five times more likely to be in a fatal crash. They are also less likely to stay at accident scenes, according to Yale Law School’s Jerome N. Frank Legal Services Organisation. The costs of accidents involving the uninsured are passed on to other motorists in the form of higher insurance premiums.

All this explains why Dannel Malloy, Connecticut’s governor, signed a bill on June 7th allowing illegal immigrants to apply for driving licences from 2015. Opponents complain that the recipients will use their new identity cards to obtain welfare, though this is forbidden.

New Mexico, which began issuing licences to illegals in 2003, saw a 23% decrease in traffic deaths between 2002 and 2010. The proportion of motorists in the state who are uninsured has fallen from 33% to 9% since 2003.

The list of states that give documents to the undocumented is growing. Colorado’s governor signed a bill on June 5th. Nevada, Oregon, Maryland and Illinois have all passed laws this year. The biggest prize would be California, home to almost a quarter of illegal immigrants. The state Assembly recently passed a bill, but it may die in the state Senate.

Not all the trends are liberal. New York abandoned a bill in 2007. Nebraska and Arizona deny licences even to “DREAMers” (undocumented immigrants brought to America as children). In Arizona, activists are suing the governor to change this. On June 11th Nebraska’s “DREAMers” filed suit, too. And New Mexico’s Latina Republican governor has for years battled to toughen its law; her latest attempt failed in March.