Q I was driving on University Avenue in Los Altos where there are signs warning drivers of upcoming "Speed Humps." But on Pierce Road in Saratoga, signs warn drivers of "Speed Bumps." What is the difference between a bump and a hump?

Mike Odenheimer

Saratoga

A Speed humps generally provide more gradual vertical deflection than speed bumps. Speed bumps limit the speed of traffic more severely than speed humps. Steve-the-Traffic-Man says, "This difference in engineering terminology is not well known by the public, and for signing purposes the terms are interchangeable".

Q Pretty much weekly, but mostly on Fridays, a 20-foot BiRite food service delivery truck parks in the right lane of northbound Lincoln Avenue in Willow Glen right during morning commute. While I'm certain this doesn't pass normal common sense as OK and there's a cross street 100 feet around the corner, is it legal?

Pete Williams

San Jose

A Technically, this is not legal. However, police know that many trucks need to park like this in order to deliver their goods. These trucks would have an almost impossible task if they had to park on nearby residential streets.

Q Has anyone ever calculated the cost in dollars or perhaps the amount of kilowatt-hours it takes to charge an electric car? Sure, the cars puts out zero emissions, but what about the charging cost for driving 100 or 150 miles?

Hermann Rehmeyer

Sunnyvale

A Here it is. If electricity costs 11-plus cents per kWh and the vehicle consumes 34 kWh to travel 100 miles, the cost per mile is about 4 cents. Charging an all-electric vehicle with a 70-mile range (assuming a 24 kWh battery) would cost about $2.64 to reach a full charge.

By comparison, the cost to operate a medium-sized gas-powered car for gas and oil is around 15 cents a mile based on current gas prices, according to AAA.

Q Will Caltrans EVER do something about the Highway 101/Highway 92/Hillsdale Road mess? This awful exit, which has traffic from Hillsdale trying to get onto 101 north while 101 traffic tries to cut through to get in line for the 92 exit, backs up 101 traffic for miles EVERY SINGLE AFTERNOON! Sheeze.

Joe W.

Millbrae

A A joint study funded by regional and San Mateo County agencies is not done yet, although getting close. But they report there is no easy solution and some ideas indicate the price tag will be significant. Said Sandy-the-County-Planner: "The type of large capital project that will separate traffic going to Hillsdale from traffic going to 92 will take a long time."

Q I was a huge skeptic of Clipper. Now, I'm a fan.

I used Clipper last week on the Alameda/Oakland ferry from the Ferry Building. Using Clipper, the ferry ride cost $4.75 compared to $6.25 for a paper ticket. On Caltrain, using Clipper saves you a quarter! But it's more than that.

On the walkway to the ferry, there are several Clipper machines to tap your card. I just tap my wallet to the machine. Ditto on the trip off the ferry.

To all those folks who complain about Clipper: Tell them to go to Walgreens and buy a card and put some e-cash value on it. It won't expire, and it just may cause them to take a trip on transit.

Every time I see those queues of transit riders by the BART ticket machines, knowing they just got off Caltrain, well, it just makes no sense. They could use one electronic smart card to pay for both rides, and no queuing to buy paper tickets. How do you spell convenience?

Irvin Dawid

Burlingame

A C-L-I-P-P-E-R?

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