Expect mediocrity and you'll get it.

Sadly, the MTA apparently expects mediocrity. For subway riders, that means little hope of improvement in trains' on-time performance, which runs from 93.7% on the L line to a pathetic 49.2% on the 4 train.

An audit by state Comptroller Thomas DiNapoli released this week showed that the subways' overall on-time performance in 2014 was 74%. But DiNapoli's audit noted that instead of trying to improve that number, the MTA lowered expectations, reducing its goal for on-time performance from 91.9% to 75%. For the record, a train is on time if it reaches the end of its line within 5 minutes of its schedule.

New York City Transit claims the goal was changed so it's "both challenging and achievable." But a 75% on-time rate isn't challenging, and it certainly isn't a marker of a satisfactory performance. Even the lines with the best performances need higher standards, too -- and the worst of them shouldn't strive only for incremental improvements.

MTA officials say they're more focused on "wait assessments," or how long riders wait between trains. There, the agency increased its goals, hoping that 81% of the time, a 5-minute expected wait will be no more than 6 minutes, 15 seconds. They're close to meeting that goal -- so maybe it's time to up expectations even more there, too.

The MTA shouldn't discount the impact of delays. According to DiNapoli, there were 500,000 train delays between March 2013 and March 2014. For millions of riders, that's a staggering loss of everything from productivity and economic activity to, more simply, time for other tasks. It's unacceptable.

Instead of taking the easy way out, the MTA must try harder. Make relatively small fixes to track maintenance and customer traffic flow. Then, it's about better trains and tracks and new lines. The city and state must cover the $11.5 billion gap to fund the MTA's five-year capital plan.

Riders shouldn't expect their trains to be delayed a quarter of the time. Reach for a higher standard, and find ways to make it a reality.