Mike on Traffic

Traffic Engineering Fundamentals Workshop

I'll be giving a one hour presentation on traffic impact studies at Minnesota's Workshop on Traffic Engineering Fundamentals.  The one day workshop (February 11, 2009) is sponsored by the Minnesota Local Technical Assistance Program and the North Central Section of the Institute of Transportation Engineers.  Other topics that will be covered are in-pavement lighting design, I-35W bridge traffic issues, intelligent transportation systems, highway safety fundamentals handbook, and local safety initiatives.

At $75, the workshop is a great way to get lunch and a full days worth of continuing education credits.  If you are in the Twin Cities, I hope you can make it.

Inauguration Day Traffic Management

Engineers at the University of Maryland's Transportation Technology Lab have developed a "4-D" traffic model visualization that is being used for the first time today.  It is supposed to help emergency response and traffic management personnel see traffic issues clearer.  It doesn't provide any new traffic data, it just repackages it.  Check out the story and a demo at NPR. 

Developer's Consultant vs. City's Consultant

I was at a meeting yesterday discussing traffic study policies.  About half of us at the meeting were consulting traffic engineers and the other half were government employed traffic engineers.  When a traffic study is done, it is typically done in one of two ways:  (1) The developer hires a traffic engineering consultant to prepare the study and then a city staff member or city hired traffic engineering consultant reviews the study.  (2) The city has the developer escrow funds and the city uses those funds to directly hire their own consultant traffic engineer to prepare the study.

I am usually part of process 1 - hired by the developer or hired by a city to review another consultant's study.  A couple of my buddies at the table are consultants who are typically hired under scenario 2.  One of them made the comment that it is better for cities to use method 2 because the consultant isn't in the pocket of the developer (a little self serving eh?).  Well, I had to try to protect myself.

Here is my logic on why option 1 for completing traffic studies is best.  First, I assume consultants should do the same quality work no matter who the client is.  We are licensed engineers and we have a duty to the motoring public.  This is how I operate, but there are one or two consultants in my town who don't have the best reputation.  So, I believe in the trust but verify method.  Second, in the real world there is always a gray area between the black and white.  This is an area often referred to as "engineering judgment."  In option 2, you only get one engineer's opinion of the gray area.  In option 1, you get two opinions.  Sometimes they agree and sometimes they don't.  It is important though that the gray area can be highlighted and the different traffic engineers have a chance to back-up their engineering judgment.  Ultimately then, the city officials choose where they want to come down on the matter.

Going with option #2 is kind of like a court system hiring one expert witness and trusting their judgment.  This may work out fine, but there is no quality control in that scenario.   When I sat in a city traffic engineer seat, I caught mistakes my consultants made.  Nobody is perfect.  I like the redundancy of option 1 because there is a better chance the right thing will ultimately be done.

St. Paul's Traffic Management at the 2008 RNC

I attended a luncheon yesterday where John Maczko, St. Paul's city engineer (he rose up through the traffic engineering division), gave a recap of this past summer's Republican National Convention.  He touched on all of the detour planning and signal re-timing efforts that went into a third of downtown St. Paul being shutdown.  Six lessons I took away from John's presentation for any Public Works folks who may be involved with a future national convention:

1. Push your way to a seat at the table.  Secret Service and Police Agencies are running the show and they are not inclined to be inclusive. 
2. Have clearly defined point people.  Everyone needs to answer to one person.  Hooligans may impersonate police officers, so the public works folks at the event may need to confirm authorization.
3. Have dump trucks, loaders, and portable changeable message signs at the ready to be deployed for changing conditions.  The unexpected will happen.
4. Get as many cameras deployed as possible so you can monitor what is happening.
5. Develop a detailed traffic management plan and think through contingency plans.  Peace officers and engineers have very different personalities.  Engineers are used to planning and officers are used to reacting.  The peace officers aren't going to push you to plan, but you need to be ready.
6. You are going to train a certain subset of your public works employees to use gas masks, deal with protesters blocking streets with cars, etc.  Use them.  If you run into a situation where you don't have enough personnel, live with it.  DO NOT deploy untrained people because the security situation is critical.  You are better off being short handed than sending "lambs out to slaughter."

Traffic Calming Resources

I came across a very helpful website on traffic calming - www.TrafficCalming.org.  It simply lists traffic calming strategies and their effectiveness.  A more local resource with a lot of data, but not as simple to use, is the Local Road Research Board's site.  I have worked on some retrofit projects, but traffic calming is something that should be thought of during the design phase of subdivisions.  The overall environment is the best way to slow people down. 

Here is one of my favorite traffic calming measures -  A trike or toy on the curb lets people know they should be cautious.

Richfield's Modified Basketweave Stop Sign Pattern - One Year Later

I blogged a year ago about the City of Richfield’s policy implementing a modified basketweave stop sign system.  I was curious to find out how the policy has been working after a year of implementation.  Tom Foley, Richfield’s Transportation Engineer, was kind enough to do an interview with me.  Following is our question and answer:

Q - Have you collected any further data on the stop sign policy now that it has been in place for about a year? 

A- We have implemented the new policy in only one-third of the city. It will take another two years before stop signs are installed citywide.  We have not had a chance to collect data on speeds and crashes in the new neighborhoods that had stop signs installed in 2008. This will be done in 2009.

Q - Has the policy made your job easier or has it complicated it? 

A - The data collection of residential speed data has required increased Engineering staff time. Also, there have been a number of requests that the stop signs be reconfigured at specific intersections. We have had complaints that the new stop sign pattern has increased speeds on east-west streets. We have explained that data collection is needed to document the effect on speeding. We have had one complaint that a resident has lost on-street parking due to state law prohibiting cars from parking closer than 30 feet from a stop sign.  In one way it has made my job easier. Residents who want stop signs are willing to wait for their neighborhood to receive them.

Q - What things would you change in the policy?

A - I am satisfied with the policy. However, I would encourage other cities to offer this approach on a neighborhood by neighborhood basis. In other words, as residents request stop signs, I would ask the entire neighborhood if they want them. If they do, then you would offer them the pattern as we have proposed it, or the traditional basketweave pattern as another alternative. One of our biggest concerns was that the placement of stop signs appeared haphazard to many drivers. This could lead to crashes based on motorists thinking that all intersections are stop controlled, when, in fact, they are not. Emphasizing consistent traffic control at the neighborhood level will improve safety.

Q - Any advice for other traffic engineers looking at implementing the modified basketweave?

A - I would say that Richfield’s experience can be useful if another city is thinking of adding stop signs in residential areas. Richfield is predominantly designed with a grid pattern for its residential streets. Our findings are most suitable for other cities with a similar grid pattern street network. Using before and after speed/crash data is helpful in evaluating the effectiveness of any traffic control system in residential areas. We benefited from using our Geographic Information System (GIS) to sort and analyze a large amount of data. We also found that there was very little useful research literature available on traffic issues involving residential streets.  What we did was give transportation engineers another option in dealing with residential traffic control. This modified basketweave option should be considered in addition to the traditional basketweave stop sign pattern.

Thanks Tom!