Mike on Traffic

Driving on the left side of the road comes to America! (Missouri's Diverging Diamond Interchange)

Check out Missouri's recently opened Route 13/Interstate 44 diverging diamond interchange.  Drivers go on the left side of the road over the bridge instead of the traditional right side.  This is much more efficient for many situations because the left turners have much less delay.  Courtesy of the Missouri DOT, here's a video of the interchange in action.

Warning Signs - More Effective Alternatives?

When was the last time you saw a child playing next to a Children at Play sign, rocks falling by a Falling Rocks sign, deer crossing by a Deer X-ing sign...   Didn't we all learn the perils of "crying wolf" in kindergarten?  Because the warning signs warn of phantom dangers, our brains learn to tune them out.  Tom Vanderbilt details the research on this phenomenon very well in his book Traffic.

So what should we do along those rural county roads that have a high proportion of deer/car collisions?  I'd like to see a test done where we make up a semi-realistic looking stuffed deer - probably made out of canvas, filled with a lightweight material so it weighs about fifty pounds, with some red paint on it.  We have the county public works guys move this around the "dangerous" corridor every few days when they are making their normal rounds.  This would provide a real, semi-dynamic warning to motorists that they are on a corridor that has a lot of deer crossings.  Or we could train the deer to cross at the yellow crossing signs (apparently under bridges so they won't get wet when it rains).

Landscape Medians Enhance Traffic Safety

Thanks to Rick Perez, PE for pointing out this interesting research on landscaped medians.  Originally, the Washington DOT was concerned about the negative safety implications of planting trees in boulevards - they obstruct sight lines.  A summary of the before/after results from the report's abstract:

    Total, fatal, fixed object, pedestrian/bicycle, tree, curb/median and U-turn accident rates were analyzed. The percentages of intersection-related, driveway-related, and other accidents were analyzed. Overall, accidents decreased significantly for the treatment locations, but no other types of accidents showed significant changes at either the treatment or the control locations, except for the percentage of other types of accidents at the control locations, which increased significantly.
    It appears that the installation of landscaped medians does not have a detrimental effect on safety and may result in an overall decrease in accidents, conclusions consistent with those of the first phase.

Without boldly saying it - the research says crashes decrease on arterials with landscaped medians.  I don't think this is surprising since the before conditions and control conditions had no medians (they either had two way left turn lanes or no median/center turn lane).  It is noteworthy that the trees didn't seem to cause problems.  As usual, we could use more research to confirm the results but this is quite encouraging for us who believe in Context Sensitive Design.

Abacus - Miovision Competitor?

Guys from Iteris and Brown Traffic (Michael Wieck, Mark Fayta, & Tony Juettner) stopped by my office a few weeks ago to show me their new traffic counting product - Abacus.  I sent Michael a video clip from my Miovision recording system to see if the Abacus could do an automated turning movement count.  They tested it and said the video camera had too much motion, but they hope to revise their system within a couple of  months to handle "wiggly" video.  Right now they need a fixed camera.  A third player could be Aldis Corp who claims to be able to do turning movement counts with their camera system, but they won't return my inquiries.

I like the Miovision system, but the economics don't work very well for me here in Minnesota.  They charge per hour of video being processed.  I am not a big user, so they charge me about $25/hour.  $25/hour doesn't compete well with me sending out people if I am being hired for a few hour count.  It is also a stiff price if I want to do a 48-hour turning movement count (which I think the traffic engineering industry needs to gravitate towards).

Iteris is trying to develop a more traditional traffic counting model (like Jamar, Peek, etc.) where you buy the hardware and software up front.  Then you own the system and can charge what you want for whatever duration count you want.

Iteris could be real competition for Miovision if the Abacus can process video from a temporary, non-fixed video camera.  Michael told me the Abacus can process four intersections at a time (post processing in the shop) and they  have a $30,000 price point for the system (this doesn't include the video camera system you'll have to put out in the field).  At Miovision's $25/hour price, the Abacus would save me money after I process 1200 hours of turning movements.  Not bad.

Neither the Miovision system nor Abacus are silver bullets for me in this down economy (all things being equal I'd rather pay my people who have been with me 5+ years instead of a computer in a different country), but I believe doing turning movment counts by hand will be largely replaced by computerized systems within a few years.  The business case will eventually force me to use technology over manual labor.

Traffic Safety Plans for Schools

My son Mitch starts preschool today.  My daughters Maria and Anna start school next Tuesday along with most of the kids in Minnesota.  My girls walk a block and a half to their school (uphill both ways), so I have given some thought to their safety as they mix with traffic.  I have also worked with several schools to improve safety around their campuses.  Out of that work, I put down my thoughts on Traffic Safety School Plans in this white paper. (If that link doesn't work for you for some reason, look for the paper under the resources tab of www.SpackConsulting.com).  I hope you'll take a look at the paper and work to make a school near you safer.