How can a 3-van local delivery team cut last-mile time and fuel?

[Nora_L]

I run a small local delivery service for a few boutique stores, and our biggest bottleneck is the final leg of the trip. I've been reading about last mile delivery optimization, but most of the advice seems geared towards massive companies with complex routing software. For a fleet of three vans dealing with unpredictable downtown traffic and parking, is there a simple, practical way to shave off time and fuel, or is it just an inherently messy part of the job?