Today Gerard Keating took us for a road trip. A group of the alderman, the Mayor, a couple of folks from the city staff, some of the press and a few of the citizens of the area were all invited to see various developments in the Aurora, Naperville and Warrenville areas. In some respects, it was eye opening.

We learned why the city is pushing the Planned Development-Industrial zoning instead of Office, Research, Industrial zoning. It turns out that with ORI zoning, as long as the incoming businesses meet the zoning requirements, the city has no say in its planning. With PDI, not only must the projects meet the zoning requirements, but they must also submit their plans to the city council (and I assume the public) for approval of the project.

We also saw a few nice business parks. These developments were well manicured with nice looking buildings and a fair amount green space. As for the mix, with the exception of Farmers Insurance, the parks were by far a mix of warehousing and light manufacturing, or Office and Research and light manufacturing. The anomaly was Farmers Insurance. It was in the same park as the warehouses. they all had residential housing, schools and such near by.

What this trip did not show me was the dream Mr. Keating wants us all to believe. That he can credibly bring in a mix of businesses by starting with a warehouse. Once the warehouses are involved, office and research businesses do not follow. This fact was driven home even more when were we taken through the Cantera Business Park. This park was chalk full of offices and then had some light industrial mixed in. There were no warehouses in this park, or at least none anywhere visible from the office buildings. Several good businesses were there (I’m partially biased, my job is located in the park).

To help emphasize the fact that warehousing/logistics do not mix well, take a look at Mr. Keating’s partner in the project, The Rockefeller Group. The Rockefeller Group has build a large number of very impressive business parks as well as Free Trade Zones (logistics centers). You will find when you visit their size that there is little mixing of Logistics centers with other businesses. Their parks are quite segregated in this respect. As always there are a few exception, but they are far from the norm.

In the handout given was a letter from Metro Transportation Group Inc., the company which did the traffic studies for this project and I believe Park 88. In the letter they state

“Research and development centers produce a very small percentage of trucks (2 percent per ITE) but generate approximately five (5) times the car traffic anticipated by a logistics center. The burden of this traffic on the roadway network would presumably have a much more dramatic impact than the expected addition of a few trucks in the evening peak hour. From a purely traffic perspective and based on a common square footage, logistics centers appear to easily have the least amount of cumulative impact on the roadway network.”

This may be true, but it is a half truth. It does not tell the whole story. 5 cars do not have the same wear and tear on a road as one truck. if you just go by weight one full truck at 70,000 pounds is 35 times as heave as a 2,000 pound car. The ad fact is is that the damage is not proportional to weight. I found this over on the site

On any road, the load per vehicle axle passing over it is mainly responsible for the amount of wear. According to a series of experiments carried out in the late 1950s, called the AASHTO Road Test, it was empirically determined that the effective wear done to the road is roughly proportional to the 4th power of vehicle weight. As a result, truck traffic almost always is the exclusive ‘real’ cause of road damage.

In an example, a hypothetical car weighs half a ton per axle. A 6-axle, 38-ton truck also traveling on the same road weighs in at over 6 tons per axle. The truck causes 20,736 times the wear of the car (12 times the car’s axle load, with a power of 4, yielding 12^4 = 20,736). Actual trucks can have even higher axle loads, though there is a wide variation in the configuration of trucks, with some having larger, wider tyres, or multiple tyres per axle, which will cause the exact figures to vary. While such figures sound dramatic, it should be realised that a single car causes almost no wear at all, so 20,000 times this figure still may not be very high. The wear is only measurable over an extended period.

Now, one has to understand that this test was performed a long time ago and only reflects the damage of the type of road used in the test. With that said, it shows that the damage is not directly proportional to the axle wight of the vehicle.

I don’t know how much more of a dramatic effect cars can have on the road network than the trucks than this! Sure, the Mr Keating and the Rockefeller Group are going to pave over Gurler Rd. with additional asphalt to bring it up to standard for handling trucks, but after 5 years of heavy truck usage tears it up because they didn’t put in a real road, who is going to have to pay to rebuild the road? Not them! It will be us, you and me!