I think there are a lot of usability problems with the start and end fields. I entered "57th and Broadway" into the start and saw the following results:
* Broadway & 57th Street, Woodside, NY
Broadway & 57th Street, Woodside, NY
* Broadway & 57th Street, West New...
Broadway & 57th Street, West New York,...
* West 57th Street & Broadway, New...
West 57th Street & Broadway, New York,...
I quickly clicked the first link, assuming it would be Manhattan (since the map was centered over Manhattan). I got directions from Queens.
I went back and tried again clicking the second result. This time I got directions from Union City, NJ.
I didn't get the right start point until the 3rd try, and that was only after trial and error. You incur a huge cognitive load to examine each of those three options and select the correct one, when other services I use all the time (Google Maps, Hopstop, etc.) seem to get it right on the first try.
You might say this is an unfair critique, because New York has a lot of streets with similar names... but it IS the biggest city in the US, and the application IS called CityMapper.
There are four different Broadways in New York (the Manhattan/Bronx one, and one apiece for the three remaining boroughs). Two of them (the Manhattan one, obviously, and the Queens one) intersect with some sort of 57th Street.
As a user, you probably want the Manhattan one unless you specify a borough. But as a developer, it's really hacky-feeling to hardcode "this one should immediately be preferred for no apparent technical reason".
I came across a similar problem once for searches that return identically named cities. It turns out that you get pretty close to DWIM if you rank the results by a combination of population and distance-to-current location (that is, you probably do want the smaller city if it happens to be really close).
People really like CityMapper for London, but I tried it for NYC and had to give up quickly. The routes were obviously wrong; it would often pick subways that were inefficient.
For example, preferring a route requiring two transfers taking 40mins over walking one block to another station and taking a subway that required only one transfer and takes 35mins; and I don't mean just that it preferred the inefficient route, it neglected to show the more efficient ones.
I went back to Google because I felt like I couldn't trust CityMapper's results.
I went back and tried again clicking the second result. This time I got directions from Union City, NJ.
I didn't get the right start point until the 3rd try, and that was only after trial and error. You incur a huge cognitive load to examine each of those three options and select the correct one, when other services I use all the time (Google Maps, Hopstop, etc.) seem to get it right on the first try.
You might say this is an unfair critique, because New York has a lot of streets with similar names... but it IS the biggest city in the US, and the application IS called CityMapper.