NY 400, known as the Aurora Expressway, is a freeway bypassing NY 16 south of Buffalo. The road mainly serves commuters by connecting the Village of East Aurora to the Thruway.
| Mile | Northbound | Southbound | Notes |
|---|---|---|---|
| Erie County | |||
| Speed Limit 40 | |||
| 0.0 |   |
 Olean Road Richardson Road |
Roundabout |
| Speed Limit 65 | Speed Limit 40 | ||
| Speed Limit 55 | |||
| 2.2 |  East Aurora |
||
|
 |
||
| 4.1 |   East Aurora |
||
| 7.1 | Maple Street | ||
| 8.4 | Jamison Road Elma |
||
| 12.0 |  East NorthTransit Road |
||
| 12.0 | West South Transit Road |
||
| 15.0 |  Union Road |
||
| Speed Limit 55 | Speed Limit 65 | ||
| 16.4 | Seneca Street |
Seneca Street West Seneca |
|
| 16.9 |  EastBuffalo |
Thruway | |
| 16.9 | West Erie |
|
Thruway |
| Speed Limit 55 | |||
| Erie County | |||