As with many local communities, any neighborhood with a school nearby will see traffic increase substantially during morning drop-offs and afternoon pickups. With the loss of school buses and paranoid parents driving their kids to school so they can be "safe", traffic congestion before and after school can be worse than peak commuter hours. An article in the Los Altos Town Crier talks about the issue of traffic near Blach Junior High school.
The neighborhood around Blach Junior High school in central Los Altos is one of the places where traffic is a major issue. A lot of people use Covington Road as a cut-through between Miramonte and Grant Roads. There's traffic with St. Francis High School and El Camino Hospital. The issue being discussed tonight is about allowing parking on Altamead and Carmel Terrace as well permit parking and drop-offs. For people dropping kids off at school, the rules present a major issue.
I used to live on a cul-de-sac close to Blach Junior High and found that the traffic during school hours and at school events was a major turn-off to an otherwise great neighborhood. The issue the morning hours in particular is that the intersection of Covington and Miramonte gets traffic going to Loyola, Blach, and St. Francis schools as well as commuter traffic and general resident traffic. It can be a 10-15 minute wait just to get through the stop sign.
Traffic congestion may get worse with the construction of new homes at the intersection of Grant and Covington. While traffic studies show a small difference in traffic, since that intersection is only two blocks way from Blach Junior High, I would expect the folks in Los Altos to take that into account as well.