Measures of Speeding from a GPS-based Travel Behavior Survey

Recently published


Objective: Lacking information about actual driving speed on most roads in the Minneapolis–St. Paul region, we determine car speeds using observations from a Global Positioning System (GPS)-based travel survey. Speed of travel determines the likelihood and consequences of collisions. We identify the road segments where speeding occurs. This article then analyzes the relationship between link length, traveler characteristics, and speeding using GPS data collected from 152 individuals over a 7-day period as part of the Minneapolis–St. Paul Travel Behavior Inventory.

Methods: To investigate the relationship, we employed an algorithm and process to accurately match the GPS data with geographic information system (GIS) databases. Comparing actual travel speed from GPS data with posted speed limits, we measure where and when speeding occurs and by whom. We posit that link length and demographics shape the decision to speed.

Results: Speeding is widespread under both high speed limits (e.g., 60 mph [97 km/h]) and low speed limits (less than 25 mph [40 km/h]); in contrast, speeding is less common at 30–35 mph (48–56 km/h). The results suggest that driving patterns depend on the road type. We also find that when there are many intersections, the average link speed (and speeding) drops. Long links are conducive to speeding. Younger drivers and more educated drivers also speed more, and speeding occurs more often in the evening.

Conclusions: Road design and link length (or its converse, frequency of intersections) affect the likelihood of speeding. Use of increasingly available GPS data allows more systematic empirical analysis of designs and topologies that are conducive to road safety.

Choice of High Occupancy/Toll Lanes under Alternative Pricing Strategies

Recently published:


Figure 2. Price-reliability model.

High occupancy/toll (HOT) lanes typically vary tolls charged to single occupant vehicles, with the toll increasing during congested periods. The toll is usually tied to time of day or to the density of vehicles in the HOT lane. The purpose of raising the toll with congestion is to discourage demand sufficiently to maintain travel speeds in the HOT lane. However, it has been demonstrated that the HOT toll may act as a signal of downstream congestion (in both general purpose (GP) and HOT lanes), causing an increase in demand for the HOT lane, at least at lower prices. This paper develops a model of lane choice to evaluate alternative HOT lane pricing strategies, including the use of GP density, to more accurately reflect the value of the HOT lane. In addition, the paper explores the potential effect these strategies would have on the HOT lane vehicle share through a partial equilibrium analysis. This analysis demonstrates the change in demand elasticity with price, showing the point at which drivers switch from a positive to negative elasticity.

The I-35W Bridge Collapse, Ten Years On

August 1 marks the tenth anniversary of the tragic and shocking collapse of the I-35W Mississippi River Bridge in Minneapolis.

Around the fifth anniversary, I did an 8-part blog series on the subject, which is worth re-upping:


Motivated by the collapse, we conducted a number of inter-related studies, powered empirically by traffic and GPS data collected before and after the bridge reopening:

The nice thing from a scientific perspective was the ability to use the GPS data collected before and after the bridge reopening for other studies as well, the data comprised part of four of my student’s dissertations, and several from Henry Liu’s students.


Another thing to note, from a career perspective, was that this research agenda was an unanticipated turn. Though I had done some empirical route choice studies before hand, and so was primed to take this direction, I was moving more into the transport and land use and network evolution realm. If you had asked me on July 31, 2007 what I would start working on on August 2, 2007, this was not it.

On Benefit / Cost Analysis and Project Selection in Transport

Before I left Minnesota I was asked by a Representative in the Legislature how to improve Department of Transportation project selection (following up on this presentation in February). I wrote back this (I revised and extended my remarks for the blog):

A Political Economy of Access: Infrastructure, Networks, Cities, and Institutions by David M. Levinson and David A. King
A Political Economy of Access: Infrastructure, Networks, Cities, and Institutions by David M. Levinson and David A. King

What are transport “needs”? It’s simple, a project is a “need” when the full benefits exceed the full costs. [Clearly very few projects are a “need” in an existential sense, but what we are talking about are more than “wants” in that they are net benefits for society, by definition.]

Measuring benefits and costs can be tricky, but it is not impossible to get a first order estimate, and the general principle is straight-forward. Sadly almost no agency requires actual benefit/cost analysis.

So I would suggest rules something like:

  1. All highway, transit, airport, and port projects that are considered in project-selection processes involving expenditure of state or federal funds above $5 million shall undergo a consistent, peer-reviewed, monetized benefit/cost analysis that would
    • Consider the full benefits and full costs of the project (in comparison with a no-build alternative) incorporating changes in: number of passengers and freight, travel time and travel time reliability, accessibility to employment and workforce, land value, wider economic benefits, crashes and crash severity, air, water, land, noise, pollution costs, and carbon emissions, public health (including both physical activity and pollution levels), vehicle operating costs, as well as the costs of building, maintaining, and operating the project over time.
    • Consider these costs and benefits distinctly for the population as a whole as well as any relevant transportation disadvantaged groups
    • Consider these costs and benefits not only for the project, but for the relevant portion of the transportation network, including related transportation sections both upstream and downstream of the project and competing with the project.
    • Consider uncertainty bounds in the estimation
  2. These analyses must be performed according to a standard methodology published by the Department of Transportation (DOT).
  3. The methodology and analyses shall be reviewed every two years by a national panel of transport and economics experts convened by DOT.
  4. The results of these analyses, including both the final results as well as the component estimations, shall be made public and posted on the DOT website in a readily accessible manner. An Annual Report of considered and selected projects shall be provided with the full benefits and full costs reported, and justification provided for any projects that were selected over other projects with higher expected benefit/cost ratios.
  5. In order to improve travel and cost forecasting, and provide an understanding of the accuracy of such forecasts:
    • The project-delivering agency shall review project cost estimates made at the time the project was approved for construction upon completion of the project, and report to the Legislature a table of expected and actual cost expenditures for all projects.
    • The agency shall review travel demand estimates made at the time the project was approved for construction 5, 10, and 20 years after completion of the project and report to the Legislature a table of expected travel and actual travel for all projects.

The City is flatter: Changing patterns of job and labor access

Recently published:

Standard deviational ellipse: Accessibility to 750,000 jobs or more within 20 minutes in the AM peak: 1995-2005
Standard deviational ellipse: Accessibility to 750,000 jobs or more within 20 minutes in the AM peak: 1995-2005


This study measures accessibility by automobile for the Minneapolis – Saint Paul (Twin Cities) region from 1995 to 2005. In contrast to most previous analyses of accessibility, this study uses travel time estimates derived, to the extent possible, from actual observations of network performance by time of day. A set of cumulative opportunity measures are computed with transport analysis zones (TAZs) as the unit of analysis for 1995 and 2005. Analysis of the changes in accessibility by location over the period of study reveals that, for the majority of locations in the region, accessibility increased over this period, though the increases were not uniform. A “flattening” or convergence of levels of accessibility across locations was observed over time, with faster-growing suburban locations gaining the most in terms of employment accessibility. An effort to decompose the causes of changes in accessibility into components related to transport network structure and land use (opportunity location) reveals that both causes make a contribution to increasing accessibility, though the effects of changes to the transportation network tend to be more location-specific. Overall, the results of the study demonstrate the feasibility and relevance of using accessibility as a key performance measure to describe the regional transport system.


Gridding West Midway |

Midway West District Current and Future Roads sketch
Midway West District Current and Future Roads sketch

Neighborhoods change. Technologies change. Economies change. While today a Distribution Center is advantageous in the West Midway Industrial Area, because the sunk costs are sunk and all the buildings are built and relocating is expensive, that might not always be true. Eventually these structures will be obsolete for the demands of the day, or a newer and higher use will bid them out. Today, newer distribution centers tend to be in the outer suburbs with better freeway access.

Recently the Green Line was opened with a station nearby, and much of this industrial land is within walking distance of the Raymond Avenue station (which to be precise is entirely east of Raymond Avenue). When this neighborhood changes, it might be wise to break up the large industrially-optimal superblocks for a more residentially-optimal fine grained grid. Change sometimes occurs quickly. Providing more East-West connectivity is especially important, so not all traffic is driven down to University Avenue. It might be wise to get those lines in the plan before proposals come before City to redevelop, so those redevelopments can it least be required to dedicate the right-of-way if not building the appropriate streets.

Getting this exactly right is not critical, there is no anticipatable precisely perfect location for future streets in a changing, adaptable world. Getting this basically right is important, a fine-meshed grid makes a difference for local circulation. However, knowing this is likely to be piecemeal, and knowing that roads should be and will be built opportunistically, but should not taking existing buildings with thriving businesses, means a rough sketch should be drawn with contingencies. The attached figure is a rough sketch.

The top black line and red lines are  the posited or dreamed about westward extension of the Pierce Butler Route, denoted for reference. The blue lines illustrate a finer meshed grid in this area. Think about them as respecting property lines where possible, going through currently paved but unstructured land where possible. The most important pieces are making sure all the East-West streets connect to Vandalia Street, and thus to I-94, and making sure the North-South streets connect to Territorial Road, and thus to Mn-280.

From east to west, the map shows

  1. a new North-South street breaking up the superblock from Charles Avenue to the end of Capp Road
  2. a second new North-South street breaking up the second superblock from Territorial to Capp Road.

These streets are circulatory in nature, and designed for access to properties in a redeveloped site.

From south to north, the map shows in blue

  1. Territorial extending to Transfer Road, through the old Amtrak station, across Railroad tracks, and into Minnehaha Avenue. Traffic calm to suit.
  2. Ellis Avenue extending to Hampden Avenue
  3. Wycliff Avenue extending to Transfer Road

These streets should achieve the aims of an extended Pierce Butler Route without running rough through the St. Anthony Park neighborhood. In particular, by directing  traffic toward Vandalia and Territorial, and thus to freeways, it should reduce through traffic in other areas and stray trucks on streets that should be more pedestrian and transit oriented.


Cross-posted at

Piercing Butler |

The most famous Pierce Butler was a founding father and US Senator from South Carolina. An apparently unrelated Pierce Butler was the first Supreme Court justice from the state of Minnesota, after earning his chops as a lawyer for the James J. Hill interests (Jame McClure writes about him on the web at Saint Paul Historical). It is this second Pierce Butler (one of many) for whom the Pierce Butler route (map) in St. Paul is named. The Pierce Butler route runs south of the east-west railroad mainline through St. Paul, complementing Energy Park Drive to the north. It progresses from Transfer Road, home of the classic mid-late twentieth century future-to-be-restored Midway Amtrak station that served Twin Citizens for decades, below Snelling Avenue, terminating at Minnehaha Avenue just shy of Dale Street.

Pierce Butler, American jurist
Pierce Butler, American jurist

It serves primarily industrial land uses, with some abutting residential.

There is a plan to extend it eastward to connect with Pennsylvania Avenue, and thus I-35E (and onto Phalen Boulevard). Jane McClure wrote about the controversy in 2009 in “Fight over eastern extension of Pierce Butler Route continues,” as did Chris Havens in the similarly timed “Push to extend Pierce Butler could be costly for St. Paul.” Such a route would function as a “reliever” for roads like Minnehaha Avenue and University Avenue, attracting truck traffic off those roads. It would also induce more east-west trips.

As far as I can tell, this eastward extension has not been moved forward in six years.

There is a dream (I dare not call it a plan, since it doesn’t rise to that level of officialness) to extend it westward to connect with Granary Road in Minneapolis through the St. Anthony neighborhood. The concept is to run it along the Railroad tracks, on Capp Road, connect to or parallel Robbins Street through the Community Gardens on the north side of Robbins Street, under Mn 280 to Granary Road.  On first blush from a transportation perspective, this seems a logical route. It doesn’t take any houses, it increases connectivity so traffic can be more dispersed, and gets “wandering” trucks off of more obviously residential streets.

The St. Anthony Park neighborhood opposes this. People garden in the local community gardens (though surely these gardens could be re-sited). Local politicians have said “Pierce Butler Route will not be extended into St. Anthony Park.” If politicians were perfect forecasters or highly powerful or unflinchingly ethically who were in office forever, we might take them at their word, however as community groups have long realized, fighting a line on a map is a forever war. Once it is built it is not easily unbuilt. But while still unbuilt, that is a more easily reversed decision.

Pierce Butler's Route
Pierce Butler’s Route

Yet, the western extension of Pierce Butler makes little sense from a freight distribution perspective. Granary Road/Pierce Butler would not interchange directly with Minnesota 280 in any case, the interchange spacings are too tight. Instead traffic would be routed north to Energy Park somehow (e.g. circling back to Raymond Avenue or across railroad tracks) or south to the intersection at Territorial Road, which they can do now (and could do better if Territorial were eventually extended to Transfer Road).

Going further west, Granary Road would run into Saint Anthony Main, bypassing Dinkytown, and not directly intersect with I-35W either, requiring local streets for the connection. While Saint Anthony Main is a lovely place, it is no longer a freight destination. None of which is to say a Granary Road for the circulation of vehicles in the neighborhoods of St. Anthony Park and the University of Minnesota wouldn’t be valuable, and better access to Saint Anthony Main from Saint Anthony Park in Saint Paul is not of itself a terrible idea, but not one justifiable from a freight perspective.

The industrial/distribution center neighborhood immediately to the east of St. Anthony Park (the West Midway Industrial Area) is still economically active. To extend Pierce Butler would likely require taking at least one building between Capp Road and Transfer Road (or skirting around it very circuitously). Building the Pierce Butler route to serve trucks by destroying one of the buildings the trucks serve is right out of an O Henry story: The Gift of the Magi.


Cross-posted at

Straightening your route |

While I don’t ride it as a regular, I have on occasion* found myself on the number 2 bus.  It offends my sensibilities as a transportation planner. It runs along Franklin Avenue from near Hennepin Avenue S to the University of Minnesota and then runs along 8th St SE to Hennepin Avenue SE. Each of the tails is sensible enough, no one really rides from one end to the other. The problem is the zig-zag in the middle.

This route has had essentially this structure since before the Green Line (actually before the Blue Line). A transit historian could tell us when it started, as it clearly does not exactly follow any one streetcar line, instead it circumlocutes. So from Franklin it does a ~120 degree turn and goes up Riverside Avenue to pick up the Fairview Riverside campus (M-Health) and Augsburg College. It does another ~120 degree turn when It stops at the West Bank Station, and then runs along Washington Avenue to East Bank, turns at Oak Street and then again at University Avenue/4th Street which is essentially a third 120 degree turn. It crosses the same line of longitude 4 times.  It then turns at 10th Avenue.

Metro Transit Route 2
Metro Transit Route 2
Imagine we removed all this zigging and zagging and zegging. Instead it would turn at 20th Avenue, picking up the other side of Augsburg College, coming within 2 blocks of Fairview University, and then to the West Bank. Anyone traveling to East Bank could transfer to the Green Line or a Campus Connector, It would proceed across the 19th Avenue/10th Avenue Bridge and resume its route. This would shorten the route by a couple of miles in each direction. It would be less convenient for some riders, but more convenient for others. More importantly, because the route was shorter, more runs per day could be achieved on this or other routes. No coverage would be lost. Franklin still has the 67 bus (see below). Riverside still has the 7 bus. Washington Avenue still has the Green Line. University Avenue still has the 6 bus.

I am sure there were reasons the bus ran this way. They might have made sense at the time. I am sure there are reasons the bus still runs this way. They make less sense now. Someone will school me in the comments.

Metro Transit Route 67, selection
Metro Transit Route 67, selection
The number 67 bus, which I take more often, though by no means daily, generally to get to the Franklin LRT, but sometimes in the other direction to get to St. Paul if I don’t want to take the LRT (since the travel time is almost identical) also offends my sensibilities, though to a much lesser amount. It was created along with the Green Line (replacing the number 8 bus), and has been modified since. I have more sympathies for the planners in this case, since it is a low volume route in these parts and needs to hunt for passengers. It runs east from downtown St. Paul along Minnehaha and Thomas Avenues, and then University and Franklin Avenues. So far so good. It follows Franklin across the River to Riverside and turns on Riverside, presumably to pick up the very same Fairview Riverside Medical / M-Health complex and Augsburg College as the number 2 bus, and then turns down the curvaceous 26th Avenue S back to Franklin Avenue, terminating at the Franklin Avenue LRT. This detour is not long in the scheme of things, and only crosses the same line of Longitude 3 times. From a far distance it looks like a pimple. But from the point of view of the passenger, I could get off the bus, walk to the next stop on Franklin Avenue, and get back on again.  If it went up Riverside to Cedar-Riverside station, I would understand the detour more. Recognizing this would leave only the 2 bus – above serving Franklin, and I just said don’t do that, I would keep it straight on Franklin though. Riverside still has service as well from the 7 bus, so losing the 67 won’t matter much.

All of this is to say that straighter routes cost passengers extra walking access time, but save them both in-vehicle time and waiting time (since shorter routes can have higher frequency for the same resources). All of which seems like a good trade-off given our current position.

I have previously commented on the spiral routing of the 87 bus.

Transit routes with proposed reconfiguration shown for Routes 2 (brown) and 67 (purple).
Transit routes with proposed reconfiguration shown for Routes 2 (brown) and 67 (purple).
What other bus routes would you reconfigure? Discuss below.

* The occasion was carelessly taking the Blue Line instead of the Green Line out of downtown and needing to get back to campus.



Cross-posted at

Fixing the 280 |

Minnesota 280 was first opened in 1959, an element of a freeway network that was not fully realized. It was designed before Interstate standards became standard.  It is an important route, providing access from I-94 west-bound to I-35W northbound, a link that is otherwise missing from the network.  Wikipedia writes:

Highway 280 was authorized on July 1, 1949,[3] but did not begin construction until 1955. It was completed between Highway 36 and Kasota Avenue in 1959[4][5] and to University Avenue (at that time, highways 125256, and 218) in 1961.[6][7] The highway was linked to Interstate 94 in 1968 upon the freeway’s completion between Minneapolis and St. Paul.[8][9]

South of Como Avenue, 280 was widened and its ramps improved in the mid-1990s. The Larpenteur Avenue/East Hennepin Avenue interchange in Lauderdale was reconstructed in 2009 to eliminate the tight, no-acceleration-lane ramps. The intersection at County Road B was also closed permanently in 2009, as were the unsignaled intersections at Roselawn Avenue and Walnut Street. With construction completed in December 2009, the signal at Broadway Street was modified to allow left turns from northbound 280, thus maintaining a stoplight for southbound 280 only, but Broadway Street traffic can now only turn right (south). Thus, 280 is now in a sense a northbound freeway only, with a single stoplight for southbound traffic.

The 2009 construction project also rehabilitated the concrete pavement between Interstate 94 and Territorial Road. The project also included replacement of the BNSF Railroad bridge on Larpenteur Avenue west of 280; placement of a new median on 280 from south of Como Avenue to Larpenteur Avenue; and noise walls along 280’s east side.

Highway 280 was originally proposed (in the 1960s) to continue farther, turning westward south of its Interstate 94 junction in Saint Paul, and then continuing west into Minneapolis as a freeway running roughly along 28th Street. The route would have continued westbound to about France Avenue South. That freeway was never built, and the ramp stubs at Saint Paul’s 94/280 junction were removed in the early 1980s.

There are several problems.

Its first exit, going northbound is at “University Avenue”, but this really means Franklin Avenue and University Avenue and Territorial Road. The first entrance onto 280 NB after I-94 is from University Avenue and Territorial Road (via Cromwell Avenue, which functions as a one-way frontage road). This often results in spillover traffic on the short NB stub of Cromwell between University and Franklin. This is compounded by traffic signal cycles which are periodically interrupted by the Green Line, while the Green Line itself is often delayed at this intersection. When the intersection was designed, there was no LRT on University Avenue.

Its last exit, going southbound, is to Eustis Street (marked as Robbins Street on the attached figure from Google Maps, it’s not clear where one ends and the other begins). Its last entrance is from Franklin Avenue and Eustis Street (which functions as a SB frontage road), but this is complicated and split into two entrances, one which goes to I-94 EB, (merging with the left lane of Mn280 SB), and one which goes to I-94 WB (merging with the right lane of Mn 280 SB). This split is because it is so close to the highway that weaving is undesirable. However this creates a very awkward dog-leg at Franklin to I-94 EB, trucks taking this dogleg often block both directions of traffic.

When I-94 is congested for some reason (an incident, weather), cut-through traffic uses Franklin Avenue as an alternative in the Prospect Park neighborhood. There are efforts to calm Franklin, and bike lanes (and sidewalks!) have recently been added to the St. Paul side, and are coming to the Minneapolis side.

Minnesota State Highway 280 Reconfiguration Proposal sketch.
Minnesota State Highway 280 Reconfiguration Proposal sketch.

The figure shows a possible solution.

In brief, turn Territorial Road into the location of an urban diamond interchange, and close the entrance and exit ramps off of Franklin.

Two new ramps would need to be constructed: denoted “New Ramp A” and “New Ramp B” in the figure.

New Ramp A is straightforward to construct, and if old Ramps 2 and 3 are closed, should not create significant weaving problems with other entering/exiting traffic. It does require traffic that is going EB on I-94 to merge over 1 lane of traffic to reach the left lane exit, but I think there is sufficient room for this to take place (about 2 city blocks). There are other configurations of Mn 280 (like a mini C-D lane for merging traffic and traffic exiting to WB I-94, so lane changing is more controlled) that could make this work in the space available.

New Ramp B requires closing old Ramp 1. This is small loss. Ramp 1 is redundant with the ramp immediately north off of Territorial. I am not sure why both were constructed. Clearly it saves a stop sign for traffic from the south, but it imposes an awkward downramp onto an up-grade on 280, which creates acceleration problems, particularly for trucks.

The closure of old Ramps 2 and 3, entrances from Franklin Avenue to access I-94 are the greatest accessibility losses. Not that traffic cannot reach their desired destination, it can always use the next exits to the East (Vandalia/Cretin) for eastbound trips or west (Huron Boulevard or Riverside Ave/26th St S) for westbound trips, or circle around to Territorial Road. This latter option is up to an extra six blocks of distance for traffic on Franklin Avenue EB to reach I-94 EB. The others require little or no extra travel distance, but extra travel time if the freeways are free-flowing. (Likely very little extra time if the freeways are congested though). Reducing cut-through traffic does not come without costs, which is reducing freeway access for local traffic.

Old Ramps 4 and 5, which are exits from I-94 EB and WB/Mn-280 to Franklin and University would also be closed. Traffic would travel farther up Mn-280 before exiting. Traffic heading to Prospect Park south of University Avenue (and offices like the Court International Building) would thus have a longer trip. However this greatly reduces intersection conflicts at Franklin and University, which are ill-suited to the demands placed on them here.

This proposal reduces traffic on Franklin Avenue. It reduces traffic, especially truck traffic, crossing University Avenue and the Green Line LRT. It simplifies street patterns both locally and on Mn-280. While it will inconvenience some traffic, it will also change travel demands. As we re-learn repeatedly, build it and they will cometake it away and they will go. Traffic, like work, will expand to fill the space allotted it. This also points up the need to have better street grids in Prospect Park North and the industrial area southeast of University and Mn-280.

This also frees up space for a potential freeway cap on Mn-280 at University Avenue and at Franklin Avenue. I don’t think the demand is there now for such a thing, but land use markets change quickly.

The interchange of Mn-280 and I-94 is likely to be reconsidered as MnDOT considers implementing MnPASS lanes on I-94 between the cities (left exits and entrances mix poorly with center lane – express lanes without elevated structures or tunnels).

Note: In Southern California, interstates are not “I-this” or “California-that” or “route-the other”. They are “The ___”. A freeway in the LA area would be The 101, but don’t be caught dead saying “The 280” up in the Bay Area…they stick to the standard naming convention, sans the.



Cross-posted at