Q Lane splitting scares the &%@$*! out of me. I've never seen this in any other state, and couldn't believe it was legal here when I returned to California after many years away. Even on city streets, I might be driving with the flow of traffic, minding my own business, when all of a sudden a biker roars past me. Where in the motor vehicle code does it say it is legal for motorcyclists to do this?

Diane Bagues

San Leandro

A Nowhere is there a ban on lane splitting in the state vehicle code, and for years the CHP has interpreted this as making the practice legal at low speeds. But with motorcycle deaths sharply increasing in the state -- up 17.6 percent in 2011, while overall fatalities were up 2.6 percent -- safety officials are concerned. So for the first time, the CHP has issued speed recommendations on a practice that is allowed only in California.

The guidelines released by the CHP and state Office of Traffic Safety say motorcyclists can ride between two cars only if there is room between them, only between the far two left lanes and only if traffic is moving 30 mph or slower. And the motorcycle must travel no more than 10 mph faster than the vehicles it is passing.

Nearly 9 of 10 motorcycle riders in California say they lane-split. But past surveys found only 53 percent of drivers knew lane splitting is legal, and 7 percent of drivers say they have attempted to block a lane-splitting motorcyclist from passing them.

Read the new guidelines at www.chp.ca.gov/programs/motorcycle.html or http://ots.ca.gov/lanesplittinggeneralguidelines.pdf.

Q I've been riding for 43 years, including several years as a motorcycle cop before I retired. And yes, I split lanes both on and off duty. It's worth mentioning that in congested traffic, the alternative to lane splitting is to remain sandwiched between other larger vehicles and the most common traffic collision scenario in stop-and-go traffic is a rear-end accident. Even a low-speed rear-end collision can result in serious injuries to a motorcyclist. So along with the risk involved in lane splitting, there is also a safety benefit.

Lane splitting demands a rider's full attention. Automobile drivers should remember to use signals when changing lanes -- at least three "flashes" before crossing the lane line -- in order to give unseen motorcyclists a fair warning.

David Dehaan

San Jose

A And ...

Q I'm a motorcycle commuter and lane sharing is not something I like to do. I know it upsets a lot of drivers and it is risky. When I'm in my car and a lane-splitting motorcycle roars by in a careless manner, not only does it scare me, that rider gives the rest of us more careful -- and hopefully more considerate -- riders a bad reputation.

But one night I was low on gas and decided to risk lane-sharing on Highway 237. I want to say thank you to all the kind and wonderful cars who moved over to give me extra room to squeeze through.

I try to wave "thank you" back, but I can't always do that. I need both hands on the handlebars of my quiet BMW bike so hopefully those commuters will see themselves in your column and receive my thanks through you. I can't think of a better way to let people know that we share the road and kindness is appreciated.

Cecilie Hoffman

Mountain View

A Peace and calm on a Bay Area freeway make me so happy.

Q Has anyone raised an issue with you about motorcycle riders who are acting as carpool cops? I've encountered a couple recently on Interstate 880 but I didn't realize that's what they were. I try to be considerate and straddle the outer line but then a couple of them would suddenly go in front of me and flash two fingers. I'm confused because my son sits in his car seat.

I wouldn't be writing this if it were not for this one jerk who did the same thing and slowed down. I was livid. What if I had hit him? He did this, then zoomed across three lanes to his exit. Please warn your readers that if they want to play cops, stand on their bike, like cops do, to make sure no one is in the back seat.

Better yet, leave the policing for real cops.

Jose Geronimo

Newark

A You have that right.

Have a gripe, minor annoyance or major problem with transportation? Look for Gary Richards at Facebook.com/mr.roadshow or contact him at mrroadshow@mercurynews.com or 408-920-5335. The fax number is 408-288-8060.