To determine which street travels through the region with the steepest slopes, we need to look at the index contour lines associated with each street:
- Smith Road and Shelton Road are both near index contour line 450, indicating a region with relatively mild elevation changes.
- Imperial Drive is in an area with index contour lines numbered 500, which means it is situated at a higher elevation than the other two roads.
- Thurgood Avenue is also in a region with index contour lines numbered 450, similar to Smith and Shelton Roads.
The key to identifying the steepest slopes lies in the difference in elevation between contour lines. The closer the contour lines are to each other, the steeper the slope. Since Imperial Drive is near a contour line of 500 and the others are near 450, it can be inferred that the region around Imperial Drive will have steeper slopes as it transitions from 500 to lower elevations (like 450).
Therefore, Imperial Drive travels through the region with the steepest slopes.