New York City's mayor and police commissioner called on Gov. Andrew Cuomo Tuesday to sign a bill they say could help protect police officers.

The proposal would add checking tinted windows to state automobile inspection requirements. Law enforcement officials say that when windows are tinted a darker shade than the law permits, officers are unable to see what's inside.

In 2007, NYPD Detective Russel Timoshenko was killed while approaching a stolen car with an armed person inside whose weapon could not be seen. Another officer was wounded in the same incident.

Under current law, an officer can issue a ticket when a driver has illegally tinted windows. Cuomo vetoed this same bill four years ago over concerns that equipment to check window tints was too expensive. Proponents say such equipment has come down in price since then.

The move comes after four officers were shot in as many cities during a 24-hour span this week.