How accurate is the New York subway map? When it comes to communicating how long it will take you to actually get somewhere–not especially.

So designer Nate Parrott created his own interactive subway map that shows you exactly how long it takes to get between stops. Click on your home station, and the entire map reorients to show you how many minutes it will take you to reach every other stop on the map. From there, you can filter by weekday rush hour, weekday late night, or weekend afternoon.

It’s similar to a time-based walking map from earlier this year, which shows you coffee shops or lunch spots based on how long it will take to get there, rather than geographic distance. With Parrott’s map, the same concept is applied to the subway. Combining them together would be one powerful way to get around a city.

“I grew up in N.Y.C., and I remember the first time I discovered the subway map wasn’t geographically accurate–Manhattan is hugely enlarged and distorted to make it more readable,” Parrott tells Co.Design in an email. “I love the idea of distorting maps to reflect what’s important—in most cases, and especially in New York, geographical distance isn’t.”

But his map also contains a deeper insight: that our maps could be a lot more tailored than they are now, thanks to mobile technology. “I like the idea of having a ‘personal map’ based on where you live–in the digital age, there’s no reason everyone’s map should look the same,” Parrott says.

However, Parrott’s map is based on the MTA’s train schedules–which are so frequently delayed as to render the tool useless. A personal interactive subway map will only be handy when it can tell you that you’re going to be stuck on the train for another 30 minutes.