The MBTA will start work this week to improve service on 15 of its busiest bus routes, it announced Monday.

The work will include consolidating bus stops and reducing the number of stops to drop overall trip times. The T projects the work will reduce trip times by 13 percent.

The MBTA will also make more stops accessible for disabled riders, and add amenities like shelters and benches.

Through eight communities, the 15 routes carry an estimated 40 percent of the T's total bus passengers.

The 15 routes are: