Mike on Traffic

Safe Multi-modal Traffic at Schools

In 1969, about 40% of American elementary school children walked or biked to school.  In 2001, we dropped down to about 15%.  This is due to a shift in students living more than half a mile away from their school.  Not surprisingly, kids getting dropped off in private vehicles went from 15% to 50% over that same time period.  (Source:  NHTS Data Series)

I just tuned into a webinar by the Institute of Transportation Engineers' on designing safer school site's that work for all modes of traffic (personal cars, bikes, walking, school buses, and public transit).  Here's a summary of things to consider when developing a school site design:

Picking a Good School Site for Traffic Operations

1. Situate the sight within the neighborhood being served so more kids are within half a mile of the school (half a mile is the limit of a comfortable walking distance).  Ideally in the middle of the school boundary so kids are walking from all directions.
2. Avoid access from an arterial roadway or other roads with high traffic volumes.
3. Seek multiple street fronts so the site can have driveways on two local streets or collectors.
4. Locate the driveways so any potential vehicle backups will occur on low volume, local streets.
5. Provide bike and pedestrian connections on each side of the site.

School Site Traffic Operations

1. Minimize the number of points where kids mix with cars/buses.  Avoid pedestrian routes through parking lots and across driveways.
   
2. Provide separate areas for buses and carpool pick-up/drop-offs. 
3. Provide one-way, counterclockwise traffic patterns so kids are loaded/unloaded from buses or cars right onto sidewalks.
4. Locate the bus exit within the site upstream of the automobiles so the buses have priority in getting out of the site.  This will reduce overall delay.

New "Stield" Sign

Gary Lauder designed this sign that is supposed to function in between a stop sign and a yield sign (Bill - thanks for posting this on the listserv).  I'm with Mr. Lauder in spirit - I am a proponent of using more yield signs and less stop signs.  There's no reason to come to a complete stop if there's no one else at an intersection. 

The yield sign has the same meaning as Mr. Lauder's sign, so I don't see a need for this new sign.  The idea behind a sign is that we can see the symbol and quickly determine how we are supposed to react.  There is a lot of information to absorb with the proposed sign.  Plus the placard below the sign is ambiguous at best.  Again the rules for stop signs and yield signs are crystal clear (first come, first serve - the vehicle on the right goes first if two vehicles arrived at the same time).  I like creativity, but I don't see a place for the proposed sign.

DIY Analysis - Turn Lane Needed?

      David emailed a few questions regarding the trip generation spreadsheet I posted.  He's a real estate broker trying to understand when his deals would trigger the need for a turn lane (footing the bill for a turn lane kills his development/lease deals because they aren't big enough to absorb the cost).  Here's our conversation (his questions followed by my answers in bold):

• Based on the excel file (8^th Generation ITE Trip Generation), proposed use is a free standing dollar store (Dollar General, Family Dollar), what is the recommended ITE Code?  814 – Specialty Retail
• Does the ITE Trip Generation book help calculate left turn/right turn volumes?  No.  You need to estimate a distribution pattern for the expected patrons.  This is what I get paid to do in my studies.  Developers/brokers are actually in a good position to do this for retail developments (assuming they have a market study).  Traffic engineers would typically charge $500 to $1,000 to prepare a small scale traffic study that would cover the driveway intersections.
• Also, does the ITE trip calculation take into account size of retail trade area and traffic counts?  No, it's just an aggregate of data collected around the country.  The spreadsheet provides average rates.

Trip Generation, 8th Edition UPDATED Spreadsheet

I have a previous post on our spreadsheet, which has been very popular.  Here's an update of the spreadsheet Download TripGeneration8thEdition(there was a typo for land use 820 - Shopping Center, which has been corrected - thanks Bill for the email).  Please use the new spreadsheet!

Roundabout Technical Workshop - OregonITE

  Here is a guest post from Micah Heckman of Lancaster Engineering in Portland, OR (Thanks Micah).  It's a quick report on a workshop he recently attended on roundabouts.

The roundabout workshop was somewhat useful although it may have been more useful for roadway designers.  They did have some discussion on the 2010 HCM but they did not have any examples as I was hoping.  A few things I did come away with: 

-          NCHRP 3-65/Report 572 is the basis for HCM 2010 but HCM 2010 will move beyond the NCHRP report.

-          The LOS output

o    will be based on control delay

o    will be assigned to each lane, approach, and intersection

o    delay thresholds will be the same as for TWSC and AWSC intersections

One interesting point of note was from a presentation by a representative of the City of Bend, Oregon which is a large proponent of roundabouts (I believe 28 installed since 1999 in a town of 82,000 people).  They, along with Kittelson & Assoc. worked on locally calibrating the roundabout model and found that in Bend, the critical gap was 1 second less that reported in NCHRP 572 (4.1 sec vs. 5.1 sec) and the follow-up headway was 0.5 seconds less (2.7 sec vs. 3.2 sec).  It appears as if this is a result of experience using roundabouts.  

It will be nice once HCM 2010 is released to be able to have this analysis alternative readily available.  We currently don’t do a whole lot of work with roundabouts but there are certain instances (a new development with no right-of-way restrictions) that would a good location for a roundabout.

 

Deadbeat Clients - CEI Ventures (signed by Matt Crowe) and Select Senior Living (signed by Kerry Johnson)

This certainly isn't relevant to traffic engineering, but I know other Twin Cities based traffic engineers read this blog (thanks by the way).  As a service to them, here's a warning about two clients who are deadbeats.

CEI Ventures (signed contract by Matt Crowe.  I think he folded up shop at CEI.  He's calling his latest venture Huckleberry - http://www.huckventures.com/About/MatthewCrowe.aspx)

Select Senior Living/Coventry Senior Living (signed contract by Kerry Johnson)

I know it's a tough economy out there.  I know things don't go the way developers sometimes want them to.  I also know getting stiffed is part of being in business.  That still doesn't make it right and I'd be careful of doing business with either of these companies.

I will certainly retract this post if either of them come through with payment.  I'll also let you know about any deadbeats in the future.  I'd appreciate you letting me know about other developers our community should be concerned about working for.

Virtual Crosswalk Walk Concept

Yanko Design has come up with the Virtual Wall concept (it was discussed on the ITE Traffic Engineering Listserv this week - thanks Pradeep).  It's basically a hologram that will pop up between the cars and crosswalk when pedestrians in the crosswalk have the walk signal.  Regular readers know I'm quite open to new ideas related to our industry.  This one doesn't strike me as a good one though.  

The virtual wall doesn't provide any more protection for the pedestrian.  A mom could still be turned around dealing with her baby's pacifier and blow through the intersection - hologram and all.  Sure, the mom would be at fault and would probably end up doing jail time for maiming/killing the pedestrian.  But I'd rather have pedestrians (including me and my kids) be cautious and alive instead of "right" and dead. 

Now as a traffic engineer I might be in favor of the traffic signal's computer forcing the car to brake so they can't run a red light, but I'll stop before I step into Big Brother land.

On a side note.  The picture shows the hologram up when the signal is yellow.  I'd think the hologram would pop up after the light turns red.  Imagine the liability of shooting a hologram right in front of someone's face when they're legally entering the intersection?

Should the Twin Cities add Significant Capacity to our Roads?

There was a good article in Friday's STRIB summarizing the Met Council's position that we won't have any more significant highway projects in this region.  This isn't good news for highway designers and I'm not sure it's good news for me as a traffic engineer.  But, engineers (including me) are a conservative bunch.  I don't think you'll get many of us bashing the idea of spending tax money wisely.  However, I think most engineers like to make prudent investments in the future.

We know the Twin Cities is in the top 25 when it comes to congested regions (that hits the news cycle every year when the Texas Transportation Institute releases its annual study), but is that because of a lack of investment or is it due to a mismatch between infrastructure-homes-jobs?  To get at this, I decided to see where we stand compared to the other 49 states in the Union.  I was able to find population estimates from the Census Bureau and miles of road lanes from FHWA.  The most up to date data sets I could find for both were from 2007.

I divided the number of lane miles of major road (interstates, principal arterials, minor arterials, and collectors - eliminating local roads) by the number of people in the state.  I think this is a decent estimate for how much thoroughfare pavement is in the state per person.  The results are in the table below.  We rank 11th out of 50 on the list.  Based on this quick analysis (and I grant you it is simplistic), it seems Minnesota has enough pavement per person.  As transportation engineers and planners, the time has come to shift our focus to maximizing the benefit we can gain from the investment we've already made.  At least this is what the policy makers are telling us.

Lane Miles of Thoroughfare Road per Person
South Dakota	0.0689
Wyoming	0.0642
North Dakota	0.0608
Montana	0.0519
Nebraska	0.0348
Kansas	0.0337
Iowa	0.0305
Idaho	0.0218
Oklahoma	0.0214
Arkansas	0.0213
Minnesota	0.0187
Mississippi	0.0183
New Mexico	0.0180
Vermont	0.0166
Alaska	0.0165
West Virginia	0.0152
Alabama	0.0148
Oregon	0.0146
Missouri	0.0139
Wisconsin	0.0138
Maine	0.0137
Colorado	0.0123
Kentucky	0.0122
South Carolina	0.0121
Indiana	0.0111
Utah	0.0109
Tennessee	0.0108
Texas	0.0099
Georgia	0.0094
Michigan	0.0093
Louisiana	0.0092
Washington	0.0091
Nevada	0.0082
Virginia	0.0078
New Hampshire	0.0077
Ohio	0.0076
North Carolina	0.0075
Illinois	0.0071
Pennsylvania	0.0065
Arizona	0.0064
Delaware	0.0053
California	0.0046
New York	0.0045
Florida	0.0045
Connecticut	0.0045
Maryland	0.0045
Massachusetts	0.0043
Rhode Island	0.0042
New Jersey	0.0033
Hawaii	0.0032