Response to July 3, 2002 Letter and Questionnaire
from the Senate Committee on Environment and Public Works
Submitted by The Denver Regional Council of Governments on July 23, 2002
This paper is organized according to the issues identified in the above referenced letter and questionnaire.
The difference in timing
of schedules for adopting and amending transportation and air quality plans and
for adopting conformity findings has created a situation where transportation
and air quality agencies have had to expend an enormous amount of resources to
coordinate the inconsistent federally mandated schedules.
The air quality planning process and the transportation planning process in the Denver region have accommodated conflicting federal requirements in terms of schedules for the state implementation process (SIP), Regional Transportation Plan (RTP), Transportation Improvement Program (TIP), and conformity requirements. Over the last twelve years, the process has worked only because of cooperative and collaborative efforts by the Regional Air Quality Council (RAQC), which is the lead air quality agency for the Denver area, the Air Pollution Control Division (APCD) of the Colorado Department of Health and Public Environment, the regional office of the United States Environmental Protection Agency (EPA), local project implementation agencies, including the Colorado Department of Transportation (CDOT) and the Denver Regional Council of Governments (DRCOG) as Metropolitan Planning Organization (MPO). The SIP documents for Denver are now all maintenance plans, which have been developed by the air quality planning agencies and approved or found adequate by the USEPA. Both the RAQC and the APCD as well as the EPA regional office have been very cognizant of the impact of the adoption of their documents on the transportation planning process and have modified their schedules for development and adoption of air quality planning documents so as not to negatively impact the transportation planning process.
In addition, local efforts have had to overcome inconsistent federally mandated time frames. Even though federal regulations only call for short term analysis of air quality problems, the RAQC developed a non-regulatory long-range air quality plan (Blue Print for Clean Air) which bridges the gap between the federally SIP mandated 3-10 year planning horizon on SIP documents, and the federally mandated longer range, 6 to 20 year planning timeframe of the transportation planning process documents. In addition the development of each mobile source budget has been accompanied by an informal review of long-range impacts to ensure that the Transportation Planning Process in conformity determinations can logically meet the proposed budget.
The problems encountered in the Denver area could be reduced by providing more flexibility in the SIP process for updating mobile source budgets, using more current information and models than was available when these SIP documents were prepared, and also by creating consistency between the analysis timelines for all the various documents in the air quality and transportation planning process.
The lack of congruity between the transportation and air quality schedules has had impacts on the cost of investments in highway and safety projects. At one point early in the conformity process, the Denver region was unable to proceed with new capacity projects for approximately 18 months, during which time only projects exempt from the conformity process were moved forward. During the one-year period in which we could not move forward with new capacity projects, the Colorado construction costs index increased approximately 4% percent.
The conformity process has had a larger impact on transportation funded air quality projects and activities. The process has reinforced the need for transportation projects that aid in finding conformity. An example of these projects are PM-10 programs which use local, state and federal highway funds for street de-icing and anti-icing programs and street sweeping.
The Transportation Planning Process works cooperatively with the Air Quality Planning process to develop logical air quality emissions budgets that protect public health and allow necessary transportation projects to proceed.
Experience in the Denver region has led us not to include many items as Transportation Control Measures (TCM's) in the SIP-documents. The combination of logical budgets and few legally mandated TCMs has allowed the region to process ten conformity findings in the last twelve years. Only in 1993 was the Transportation Planning Process unable to find conformity and a list of projects was adopted rather than a Transportation Improvement Program. Our inability to meet the emission budgets in 1993 was resolved by the Air Quality Planning process agreeing to make changes to the vehicle inspection and maintenance program sufficient to reduce mobile source emissions below the adopted budget and allow a conformity finding.
MOBILE6 Versus MOBILE5 Projections
There is a need for recognition in the Air Quality Planning Process of the impacts of applying Mobile6 projections in the conformity determination as compared to Mobile5 projections. The emissions budgets adopted through the Air Quality Planning Process will have to be changed to ensure conformity of the RTP in the new 2030 horizon year.
Mobile6 significantly changes estimated emissions from those estimated using Mobile5. The most significant problem for the Denver region is in terms of carbon monoxide. Our current budget is 800 tons per day. Using Mobile5 we have met this budget for all years out to our long-range planning horizon of 2025. In contrast Mobile6 emissions exceed the current budget in all future horizon years. In 2010 Mobile6 estimates approximately 1200 tons per day, 400 tons higher than the existing budget. Note that the Mobile6 rate of decrease in emissions over time is greater than that projected by Mobile5 out to all horizon years. This will greatly simplify our ability to demonstrate that a higher CO budget can be allowed while still protecting the CO National Ambient Air Quality standard (NAAQS). For other pollutants such as VOC and NOx associated with ozone and NOx associated with PM10, this problem will not exist. The emissions are less than the current budgets in all future horizon years out to 2025. In all cases the Mobile6 rate of decrease in emissions is greater than that found in Mobile5 for all horizon years.
The carbon monoxide budget will have to be changed in order for Denver to find conformity using Mobile6. This includes the budget not only through 2010 but through all horizon years. The Air Quality Planning process, with assistance from DRCOG and CDOT is moving to implement Mobile6. This will necessitate legal actions to change the budget that are currently planning for mid 2003. This should allow conformity processes to move forward for adoption of our 2030 RTP and the related sub-documents. These conformity findings are expected late in 2003 and in 2004.
It is unknown whether the new eight hour ozone standard will lead to an increase or decrease in vehicle emissions budget. The Denver region has been very close to the standard, but has not yet violated the NAAQS. If a violation of the NAAQS occurs, the Air Quality and Transportation Planning processes will have to deal with the development of new vehicle emissions budgets.
Additional Vehicle Emission Controls
Denver currently has a centralized I&M 240 program in place. It has been proposed to replace some of the centralized operation with a clean screen remote device-sensing program. The negative impact of a clean screen program versus a centralized program has already been accounted for in the maintenance plan. Implementation of clean screen is unsure, as state legislative authority has not yet been obtained.
The Denver area led the way nationally in terms of oxygenated fuel programs aimed at carbon monoxide emission reduction in wintertime. During the summer, local refineries and dealers voluntarily change fuel specifications to reduce the danger of an ozone violation. It seems unlikely that additional vehicle emission controls which can be implemented independently within the state of Colorado would be sufficient to offset the increase in emissions projected under Mobile6 for carbon monoxide.
Role of Transportation Control Measures
Adopted Transportation Control Measures play a part in attainment demonstration. Today there is only one outstanding Transportation Control Measure (TCM) not fully implemented. That project is the construction of a light rail line in the southeast (I-25) corridor. This project is included in the RTP and funded in the TIP. It has a Full Funding Grant Agreement and is projected to be completed in 2007. Credit for this is taken as an ‘on’ model emission reduction. As such, the emission reduction is not separately calculated.
The effect is CMAQ projects funded through the TIP are included in the air quality conformity documentation. These emission reduction credits are calculated ‘off’ model, with the exception of a few transit projects that are included ‘on’ model. The ‘off’ credits are not used in the conformity finding directly, but instead are considered a safety margin in meeting the emissions budgets. In past conformity findings the emission credits for such ‘off’ model projects have typically been on the order of 3 to 5 percent of total emissions.
Impacts of Conformity Lapse
Immediately after the adoption of ISTEA, and the promulgation of conformity regulations and guidelines, the Denver region was unable to show conformity for approximately eighteen months. During this time period in 1993, the Denver region adopted a list of projects (LOP) in place of a TIP. During this period of time only safety and other exempt projects could proceed forward. Other projects could not move forward if they resulted in additional highway capacity. During this year the Colorado construction index went up 3.6 percent. The project completion dates were pushed back by approximately one year because of this delay.
The impact of the March 1999 U.S. Court of Appeals decision to eliminate the EPA “grandfather” provisions from the conformity regulations was to increase the level of uncertainty concerning the Denver region’s ability to implement projects. No longer could implementing agencies assume that a project could move forward after a certain point in the planning and implementation process. This may have led to early implementation of preliminary phases of projects to get them underway and effectively grandfathered for implementation.
Role of Motor Vehicle Emission Estimates and Models
The Air Quality conformity analysis is heavily dependant upon accurate and precise estimates of motor vehicle emissions. The effect of this has been to increase the resources dedicated to development of motor vehicle emissions estimates. The emission estimates have much improved through the agency coordination and inter-agency cross checking of data and information. As the federal government did not provide additional resources for the conformity process, the dollar and manpower resources use in this analysis had to be taken from other planning efforts.
The factor that has led to the largest changes in estimates of regional motor vehicle emissions has been changes in the MOBILE models. As each generation of mobile model has been released, the estimates of emissions increased or decreased, often significantly (See Mobile5 vs. Mobile6 discussion earlier). In addition trends through time have changed with various Mobile models having more pessimistic or more optimistic views of the future. That said, the tie between emissions estimates and base year air quality monitored data, has led to comparatively accurate estimates of the air quality situation over the last ten years. As projected the Denver region has met and protected the NAAQS for public health. Monitored air quality has tended to be better than modeled air quality, but this is to be expected as the model situation was meant to represent a worse case situation.
Role of Transportation Models
The regional transportation analysis models were originally developed as planning tools. The tools were meant to project such items such as number of lanes that will be needed, transit patronage on future rapid transit lines, and the impact of major land uses on transportation. These models are now being used to develop legally binding estimates of motor vehicle emissions. The effect was to lead the environmental community to nationally question such items as how changes in highway capacity effect total travel and hence air pollution emissions. In the Denver area this resulted in changes to the highway assignment algorithm to (1) estimate 10 time periods of the day to more accurately develop air pollution estimates, and to (2) effectively match highway demand and capacity provided. It also led to a direct tie between highway speeds used in the distribution phase of the model and those estimated at the end of the model, to accurately reflect the effect of congestion on trip making.
The region’s travel models’ estimates of VMT have been checked through the Carbon Monoxide Monitoring Program, which was mandated by the 1991 Clean Act Amendment. This monitoring program continued for approximately five years and recorded deviations of approximately 1 to 4 percent in estimated vs. actual VMT.
Induced travel demand is a controversial subject over which there continues to be much debate as to its magnitude and cause. The Denver Travel Demand Model accounts for the following portions of induced traffic. First congested speeds are used in the trip distribution model. The Denver Model has a mode share model that moves travelers in highway traffic off of congested facilities and onto alternative modes such as rapid transit lines or available carpool lanes. Testing indicates that the Denver model estimates these model features lead to changes in VMT as large as 10 percent. This difference is between extreme cases of combined land use and transportation strategies contrasting centralized growth and disbursed growth and their impact on congestion. The Denver model uses steep traffic diversion curves to simulate the impact of congested roadways. This means that the introduction of additional lanes in areas where the highway network is near saturation, results in those lines being fully utilized through additional VMT that effectively represents induced demand