Mike on Traffic

Are LED Lit Pedestrian Crossing Signs Effective?

Here is a before/after study ( Download Elm Creek Blvd Ped Crossing Study) we just completed studying the effectiveness of a new push button activated, LED lit pedestrian crossing sign (thanks to Marc Culver at the City of Maple Grove for letting me share this with you).  We collected data (from video) for 12 hours on two days before and two days after the sign installation (48 hours total of data).

The hope is this type of sign would cause vehicles to yield to pedestrians more frequently than with the standard crossing signs.  Unfortunately, we found negligible difference in vehicles yielding to the pedestrians with the new signs compared to the yielding at the old signs. 

BUT, that was largely due to only 7 pedestrians pushing the button in the after condition (and 5 of those could cross without any cars coming).  The punchline is that we don't know if these LED lit signs cause vehicles to yield more frequently to pedestrians (compared to typical pedestrian crossing signs) because pedestrians don't push the buttons to turn them on.

Do Crosswalk Bumpouts Really Enhance Pedestrian Safety?

Mayor Stu Rasmussen of Silverton, Oregon sent me the following email quesitoning the effectiveness of bumpouts (aka bulbouts or curb extensions) -

I am wondering about what looks like a current fad in traffic engineering and was hoping you might have some empirical data to back up the current practice.   Bulbouts or curb extensions are the current rage for crosswalk safety modifications.  They are supposed to shorten the crossing distance and improve visibility of drivers and pedestrians for each other.

Definitely, the distance crossing active traffic lanes is reduced. To me that means that at a signalized intersection the cycle time can be accelerated because shorter distance for pedestrians means faster transit time.

 At an uncontrolled intersection the benefits are not so clear to me. If a pedestrian approaches the active traffic lane on a bumpout, does a driver really know they're going to immediately cross the street or could the pedestrian just get to the extended curb, stop, re-think their route, daydream for a while and then reverse course and wander off. All this time, the driver, if he/she is properly attentive, will be stopped while waiting for the ped to cross. After a few of these driver/pedestrian encounters it seems to me that drivers may become desensitized to the pedestrian - since it is entirely possible that no street crossing will occur.

 Conversely, _without_ a bulbout a pedestrian is _obviously_ going to cross a street if he/she has actively stepped off the (non-extended) curb and entered the parking zone of the street. There is no question in a drivers' mind of the walker's intent, and the pedestrian is clearly visible at the edge of the active traffic lane as he/she approaches.

I am wondering if there is any unbiased empirical data supporting the addition of bumpouts to crosswalks - before and after studies of accident rates with and without the bumpouts - that would shed some light on this practice.

This gave me pause because I recommended bumpouts for an issue in Pine Island, MN (read about it here).  They're highly touted in pedestrian planning documents.

I spent some time digging and couldn't find any research online about the effectiveness of bumpouts.  I did find a mention in NCHRP Report 617 on crash mitigation measures that stated no research was available on the topic.  So I posed the question to the ITE Traffic Engineers Listserv I'm on.

Dwight Kingsbury of the Florida DOT came back with this study from Oregon.  The dataset shows positive results, but the sample size isn't very big.  I think I'll stand on the side of bumpouts enhancing pedestrian safety, but more research would be nice to quantify the benefits. 

p.s.  Photo by Richard Drdul at http://flickr.com/photos/20816835@N00/180847575.

Traffic Engineering - Continuing Education

I received an interesting email from Trafficware U last week.  They're posting a lot of free resources on their site as well as providing a lot of reasonably priced webinars.  It's worth checking out.  Interestingly, a lot of the webinar instructors have also been doing webinars for ITE.

I've sat through a bunch of different webinars now.  For some reason, engineers teaching webinars doesn't work quite as well as engineers teaching in a classroom.  I can't put my finger on it, but the webinars aren't as engaging (I often come away thinking I could have gotten the same nuggets of information by flipping through the slides for five minutes on my own).  I think it's easier for the students to engage with the instructors face to face and pull more out of them.

The flipside of that - I'm waiting for one of these resources to start posting cheap recordings of their webinars.  I'd be happy to pay $25 to watch a pre-recorded webinar on a topic that's slightly relevant to me (I rarely type in questions in the webinar anyways).  I think this could be a significant money maker come license renewal time when folks are scrambling for continuing education credits.

Big Brother's Watching - Traffic Management Cameras are Everywhere

Unfortunately, chirping birds woke me up extra early yesterday morning and I rolled into the office about 6 a.m.  To my great surprise the phone rang at 6:15.  I took one more sip of coffee and answered.  It was a guy (didn't give me his name) who was clearly driving.  He said he just noticed six cameras on about a one mile stretch of highway.  He was wondering if they give speeding tickets with those.

I quickly explained about Mn/DOT's Regional Traffic Management Center which operates about 450 cameras on Twin Cities highways and no they don't give speeding tickets based on cameras in Minnesota (automated red light running enforcement was tried by Minneapolis about ten years ago and the state court found it to be illegal).

About half an hour later after the coffee kicked in I realized he must have googled freeway cameras and somehow got through to me.  Two takeaways - (1) there are lots of cameras out there so don't assume anonymity in public and (2) don't use your smart phone in the car - it's dangerous!!!

Trans-Plan Inc plagiarizes by Copying MikeOnTraffic.com

HunWen Westman (a friend of mine at Kimley-Horn) just alerted me to a blog post on the Transportation Gazette (the blog of Trans-Plan Inc)that reminded her of one of my posts.  Look for yourself -

http://thetransportationgazette.com/2010/07/what-are-pass-by-trips/

http://www.mikeontraffic.com/2009/03/what-are-passby-trips.html

They didn't even bother to update my links!  I know I'm supposed to be flattered by being copied, but I'm actually pretty pissed off.  I dug for 30 more seconds and found another copy -

http://thetransportationgazette.com/2010/06/what-is-trip-generation/

http://www.mikeontraffic.com/2008/04/trip-generation.html

I don't want to keep digging because I don't want to figure out they built their whole blog by stealing from me.  I'll let you decide if you should follow Shadi Hagag at Trans-Plan.  I hope you'll continue to come to MikeOnTraffic to read the original.

 

 

Vikings Site in Arden Hills - Initial Traffic Assessment

The Minnesota Vikings professional football (American football) team has honed in on a site in Arden Hills, MN.  You can read about the agreement with Ramsey County in the Star Tribune here (you can also hunt around the newspaper and other news sources for opinion pieces).  I'm very curious to see the traffic study that gets done for this (Mr. Wilf - we're available if you'd like our help with the traffic study). 

Below is a map that shows the location.  At first blush, the site appears to have very good freeway access from Interstates 35W and 694.  But if you look a little closer there are significant limitations for anyone trying to get to the site from the south or west (i.e. the majority of the fans).  Everyone from those directions will be forced to use the I-35W/Co Rd 96 interchange to get to the game. 

I hope they can get an off ramp built at Co Rd H, but that interchange doesn't have that move now because of the difficult weaving areas that are caused by Highway 10 and the close proximity to Highway 96.  I haven't looked into it enough to know if that's even feasible, but I assume Mn/DOT has.

Below is a scan of the conceptual site plan from my morning paper (I haven't been able to find this anywhere online - guess that's why I still get an old fashioned hard copy).  According to the team's website, the site will have about 21,000 parking stalls. 

One inbound lane can bring in about 2,000 vehicles per hour if the lane is unimpeded and traffic is rolling at a good clip (so we're being generous with this number, but it's a round number to use).  So, if we're trying to get the 21,000 fans into the site in a very chaotic 2 hours before kickoff, we better have 6 lanes of traffic rolling into the site.  The plan below is very conceptual, but I don't see that kind of access being provided. 

I hope the Vikings get a traffic engineer involved pretty soon with the site planning.  Unlike the current Metrodome site, there's no Light Rail Transit line to feed in the fans or the existing parking ramps available throughout downtown Minneapolis.   Since the site is a blank slate, the Vikings need to create all of the infrastructure to make this work.  At least there isn't much conflicting traffic for fans to contend with on a Sunday morning.

 

 

Traffic Impacts of Wind Farms

Aside from the very occasional visit from a windmill aficionado, wind farms don’t generate a lot of vehicle traffic.  But as the county engineers near the Buffalo Ridge in southwestern Minnesota know too well, that doesn’t mean wind farms don’t have an impact on the transportation system.  Each wind turbine weighs about 200,000 pounds, delivered in pieces with each truck load weighing upwards of 50,000 pounds.  These are very big, very heavy tractor trailer deliveries.

The pavement in the interstate system was designed to take the beating dished out by these deliveries, but the local roads used to get to the rural wind farm sites often don’t have pavement designed to handle these large deliveries.  The last legs of the delivery may very well be made on a gravel road.  The damage caused by these deliveries can be a huge burden to the local road authorities if remedies for addressing roads damaged by the wind turbine delivery weren’t made during the wind farm’s approval process.

The Minnesota Local Road Research Board has developed tools to help local agencies hold developers of wind farms (or other land developments with significant trucking that may damage local roadways) responsible for any road damage they cause.  The Best Practices: Managing Interactions between Local Authorities and Major Traffic Generators can be found online at http://www.lrrb.org/trafcalc.aspx.  The interactive document includes the following useful information:

• Sample ordinances, permits, agreements, and maps
• Traffic calculator spreadsheet to quantify the traffic impact on roads and its associated costs
• Policy options to recapture roadway maintenance costs

The Best Practices toolkit was assembled for the Local Road Research Board by SRF Consulting Group and Richard L. Kronick & Associates.  But just as important, the overall project was guided by a technical advisory group that consisted of representatives from many agencies including seven counties who have dealt with the impacts of wind farms.  Their first hand experience is woven throughout the interactive document.

If you’re in an area that may have future wind farm development, the Best Practices toolkit will help your agency protect its roadway infrastructure.

 

Public Employee Responsiveness (North Carolina DOT Traffic Engineer - Part 2)

A few weeks ago I posted about Kevin Lacy of the NC DOT reporting David Cox to the licensing board becasue Mr. Cox was practicing traffic engineering without a license.  "Anonymous" (anon@mous.com) submitted a clarifying comment that is worth reading at the bottom of the post.

Apparently Mr. Cox was quite prolific and persistent with his request for the traffic signal.  The interesting point of the comment from "anonymous" for me is the insinuation that the engineers are the decision makers and Mr. Cox should have left him alone once he made the decision that a traffic signal wasn't justified at the intersection. 

When I got to Maple Grove (my first and only public position) I thought the buck stopped on my desk too.  A few weeks into the job one of the council member's cats was run over on a neighborhood street.  She brought it up at the next council meeting and the council decided all way stop signs should be installed at the intersection by her house.  The city engineer (my boss Ken Ashfeld) didn't fight that decision too hard.  He came into my office the next morning and told me about the situation.  I started quoting the Manual on Uniform Traffic Control Devices on how we need to do a warrant study based on the traffic volumes to see if the intersection met the criteria for installing all way stop signs. 

Ken stopped me short and asked me how long I wanted to work for Maple Grove.  I was stunned and asked him what he met.  He explained that the politicians are elected to make decisions and that we are merely advisers to them.  The politicians delegate a lot of decisions to the staff, but they can come in and overrule us on any decision.  It's their prerogative to weigh competing factors (i.e. mobility vs. safety vs. economic development vs. public opinion etc.).  It was our role to lay out the options and make a recommendation for the elected officials to consider.  If we didn't like a decision it was always our individual pregoative to resign our position.

Ken is a very savvy city engineer (and now public works director) who has had a long, well respected tenure.  Gerry Butcher (his long time boss and predecessor as public works director) had a 30+ run with Maple Grove.  I learned from these two masters how to be a successful adviser to the city council.  Ken and Gerry would let things go like the all way stop sign at the back of a sleepy neighborhood (not a great engineering decision, but one with little downside involved), but would speak up on matters that had more significant consequences.  In those situations, the council almost always heeded their advice.  They new how to pick their battles.

Coming back to Mr. Lacy vs. Mr. Cox.  The data "anonymous" cited points to the traffic signal being a bad idea.  I typically support the position of only installing traffic signals when they are needed based on existing traffic volumes (a dirty little secret is that there are more crashes at intersections with traffic signals versus comparable intersections with just stop signs, we hope we are trading more crashes for less severe crashes).

Mr. Cox has every right as a citizen to be persistent and to go to his public representatives if he doesn't agree with a public employee's decision. It appears his request may have been extreme, but "anonymous" implies he should have taken Mr. Lacy's decision as the last word on the issue.

Based on the data in the comment from "anonymous," I would also come to the conclusion that a signal shouldn't be installed at that intersection and I would have thoroughly documented my decision (disclosure -there's a lot of he said, she said involved and I haven't reviewed the actual data).  But thanks to the lessons I learned from Mr. Ashfeld and Mr. Butcher, I would have politely absorbed Mr. Cox's attack and not stooped to reporting him to the licensing board.

Citizens Installing Their Own Stop Signs?

My friend Bob Klingel forwarded me a link to an interesting Gizmodo story about mystery stop signs in Cranston, Rhode Island.  According to the article, the city has about 650 "undocumented stop signs" (the city probably shouldn't have used the word undocumented - my favorite comment on the article - "These stop signs are stealing the jobs of good, honest, American crosswalk guards"(Edit comment)). 

The city doesn't have any paper trail on who installed these signs or why they were installed.  The article suggests residents may have put up some of the signs.

I had a resident nail a 2x4 to the road in front of his house as a homemade speed bump when I was the traffic engineer in Maple Grove (we pulled it up within a few hours of finding out about it). 

Do it yourself traffic control isn't unheard of, but I recommend leaving a few cars parked on the street to create pinch points and maybe throwing a few tricycles along the curb to warn drivers kids are around.  Trikes are much more effective than the cheesy "kids at play" signs you can buy. 

I hope the rogue sign installers called the utility locating company.  It would be quite a news story to have some guy hit a natural gas main while trying to put up his own stop sign.  And it must have been difficult to buy stop signs before the anonymity/parcel delivery provided by the internet. 

I've posted about the federal requirements for cities to keep track of their sign inventory.  The amazing part of the article is the city will probably leave 95% of the signs.  In this day of huge budget shortfalls, my goal would be to prune as many signs as possible to reduce the maintenance costs.

Problem Solved - Obama Replaces Costly High Speed Rail Plan With High Speed Bus Plan

This just in from the Onion News Network (this is satire...) - Obama Replaces Costly High Speed Rail Plan With High Speed Bus Plan.  Combine this witht he Onion's previsous finding that 98% of U.S. Commuters Favor Public Transportation For Others and we're getting somewhere!

Obama Replaces Costly High-Speed Rail Plan With High-Speed Bus Plan