John DeGrinis John DeGrinis is a senior executive VP at Colliers International.

LOS ANGELES—Solving for the last mile has become the biggest challenge for ecommerce users looking to deliver goods quickly to consumers, and it is an especially severe issue in Los Angeles, where the vacancy rate has dropped below 1%. Now, last-mile users are heading north into the valley markets to look for space that is still accessible to clientele. While the traffic into the city can be rough, there are a handful of new developments in the market that are attracting users.