Mike on Traffic

Travel Demand Management - Does it work? Real world data that says yes.

My apprentices (Mike Bultman, Joe Collins, Kirk Pettis, and Jenni Thompson) put in a lot of hard work collecting and analyzing traffic generation and parking generation data from six office complexes in Minnesota who are actively implementing Travel Demand Management (jargon alert: TDM) strategies.  Here is the full, twelve page report -  Download Travel Demand Management Effectiveness Report.  It doesn't include all of our underlying data, but we're happy to share that if there's a researcher out there who wants to slice and dice in a different way. 

Overall, TDM plans do appear to have a positive effect on traffic generation and parking numbers in buildings with TDM plans in place when compared to the Institute of Transportation Engineers published standards.  Based on the analysis performed for this study, on average, TDM plans reduce traffic generation rates by 27% to 37% and parking generation from 11% to 21% depending on the time of day and other variables.  

If office buildings implement a thorough TDM plan, they will generate less peak hour traffic and require fewer parking stalls.  We recommend practitioners use a 30% reduction in traffic generation (compared with the Institute of Transportation Engineers’ standard rates) when assessing the traffic impacts of a proposed office building that will implement a TDM plan.  We recommend practitioners use a 10% reduction in parking stall requirements (compared with the Institute of Transportation Engineers’ standard rates) for office building that will implement a TDM plan. 

These are significant findings.  The reduction in traffic generation could often be the difference between needing to install a traffic signal or not, typically a $200,000 expenditure.  In Minnesota, a surface parking stall costs between $3,000 and $4,000 to build while a stall in a parking ramp costs between $15,000 and $20,000.  This means the 181,000 square foot office labeled Site B could have built 245 parking stalls instead of 270 stalls, saving $75,000 to $100,000 in construction costs.  This does not factor in lower maintenance costs, lower environmental impacts, or the higher employee satisfaction benefits Travel Demand Management provides.

 

CVS Pharmacies: Trip Generation, Drive Through Queue, & Parking Study

We conducted a traffic (jargon - trip) generation study of existing CVS Pharmacies in the Minneapolis/St. Paul metropolitan area (Download Trip Generation Study for MN CVS Pharmacies - for NEC York & 69th in Edina MN).  While we were on site collecting manual peak period trip generation data to calibrate our mechanical tube counts with, we collected parking occupancy and drive through queue data during the weekday p.m. peak period.  Six suburban sites were surveyed from November 3, 2009 through November 7, 2009.  Each store had two drive through lanes.  

Our traffic generation results are shown in Table 1, which also shows the average rates from the Trip Generation report for comparison.  During the p.m. peak period, we observed a maximum queue of three total cars waiting in the drive through lanes.  The maximum parking occupancy during the p.m. peak period was 33 vehicles (2.54 parked stalls per 1,000s of building square feet).  Based on the data for each peak period, we expect the parking lot and drive through data to represent the peak usage.

 

Cheapest Road Tubes

I've always bought tubes for my mechanical tube counters from Jamar Technologies.  About five years ago I tried, unsuccessfully, to find a manufacturer so I could cut out paying a middle man.  Thanks to google, I've been able to track down new suppliers.  I got quotes for EPDM tubing that meets the spec of the tubes Jamar supplies (60 +/- 5 Durometer Black EPDM Tubing - ASTM D 2000 3BA620 A14 C12 F17 G21).  I tracked down prices for regular tube (.187" inside diameter x .600" outside diameter) and mini-tube (.187" ID x .365" OD).  The minimum order size was only 100 feet with each of the suppliers.  Here's what I found -

• Hanna Rubber Company:    $0.38 per foot of regular tube, $0.24 per foot of mini-tube
• Thomas A Caserta, Inc:  $0.645 per foot of regular tube, $0.425 per foot of mini-tube (note - they provide significant price breaks if you order more than 2,500 feet)
• Trigg Industries:    $0.72 per foot of regular tube, $0.44 per foot of mini-tube
• Jamar Technologies:  $0.66 per foot of regular tube, $0.45 per foot of mini-tube

As a bonus, Hanna Rubber will deliver the tubes in 50 or 60 foot lengths so we won't have to do any cutting ourselves.  Caveat emptor - I don't have first hand knowledge of working with Hanna Rubber yet, although Chad Myre has been very responsive.  I'll let you know if I have problems with their tubes when I order them this spring.

We use a mix of regular tubes and mini-tubes, but have been using more and more mini-tubes.  Washington County has used mini-tube exclusively for many years and I just found out Mn/DOT is going exclusively with mini-tubes.  In the long run, we'll probably keep a few heavy tubes around just for doing gravel roads.

Traffic Engineering Fundamentals Workshop

I'll be presenting at the Traffic Engineering Fundamentals Workshop on February 10th in St. Paul, MN (registration flyer).  The workshop is a great introduction to traffic engineering for entry level traffic engineers, technicians, city engineers, planners, etc.  It is also a great value - $75 ($50 if you're a member of NCITE) for a full day of continuing education with lunch.

The workshop has been presented annually for about 25 years now and continues to draw a good crowd.  It is sponsored by the Minnesota Local Technical Assistance Program and the North Central Section of the Institute of Transportation Engineers. Here are the topics that will be covered this year:

• Traffic Engineering:  Tips of the Trade
• Traffic Signal Operation Basics
• Encouraging and Measuring Pedestrian Traffic
• Travel Demand Management (presented by yours truly)
• Highway Safety Update

I hope to see you there!

How Big Should Your Traffic Study Be? - a helfpul matrix

I created the matrix below to make it easier to develop the appropriate scope for a traffic study.  It's based on the Institute of Transportation Engineers' recommended practice Transportation Impact Analyses for Site Development and a host of government policies I was able to find online.  All you need to use it is the development's predicted peak hour traffic (here for more on that).  Caveat:  check the reviewing agency's policies - they trump this matrix.

 

Traffic Data Inc - 2010 Data Collection Price List

I've posted our new price list at www.trafficdatainc.com.  Unlike most data collection firms, we post our price list for the whole world to see (it's valid for the seven county area around Minneapolis and St. Paul in Minnesota - quotes will be provided for projects outside of this area).  I've found my clients appreciate using our standard prices in their proposals.  That way they don't have to call me for an individual quote every time they put together a traffic study proposal - its a win-win for both of us.

I'm going to be stopping in at my regular client's to handout hardcopies and explain the price list.  We've changed our structure in three notable ways -

1. We used to do turning movement counts based on whether we thought one or two people would need to do the count in the field.  This led to a bunch of guesswork.  I've switched the pricing for turning movement counts to be based on the type of traffic control (stop signs, signals, or roundabouts) at the intersection.  I believe this makes our pricing system even clearer.
2. As I've blogged about several times, we have Miovision's video system.  This allows us to collect video of the intersection and we are now offering that as part of our pricing system.
3. I've added several low level traffic technician services.  If you get swamped, we'll work as an extension of your staff by providing field data or building your synchro network.  We'll also do warrant analysis for you.  I don't think there will be a lot of demand for this in the current economy, but I think it will allow traffic engineers to do more work without adding staff as the development economy picks up.

13 Questions for Scoping a Traffic Study

Here are thirteen questions every traffic engineer should ask when a client asks them for a traffic study proposal (developers, architects, planners, etc. - feel free to prepare answers to these questions before you call your traffic engineer for a proposal):

1. Where is it?  Ask if they have a minute so you can pull up an aerial on your computer (I am currently having the best luck with Bing^TM having up to date aerials).
2. What kind of development is it (commercial, retail, houses, industrial, etc.)?
3. How big is it (acres, gross square footage, employees, students, etc.)?  If it’s a mixed use development (a site with different kinds of uses), get a breakdown of size for each use.
4. How many accesses (driveways) are they planning?  What roads will the accesses be on?  Any existing driveways into the site?
5. When will it be fully occupied?
6. Will it be built in phases?
7. Do they have a concept or site plan they can email you? 
8. Have they discussed the traffic study with any government staff?  If yes, who?  Notes from the meeting?
9. Do they know of any nearby recent development?  Any traffic studies done for this parcel or nearby parcels?
10. When do they need the proposal?
11. When do they need the draft traffic study?
12. Will they want you to present the traffic study results at a government staff meeting, a neighborhood meeting, a public hearing at the city council, etc?
13. Are they getting other proposals for the traffic study (this is delicate, but it’s always good to know if you have competition – if you do have competition, try to find out who)?

Did I miss anything?