13.0 MN/DOT PERCEPTION TRACKING STUDY
13.1 Purpose and Approach
Mn/DOT's Perception Tracking Study measures the public's awareness, usage, and opinion of the various traffic management tools implemented by the Mn/DOT Regional Transportation Management Center and the Metropolitan District. The Perception Tracking Study was conducted in the Minneapolis-St. Paul metropolitan area on an annual basis from 1996 to 2006, except for 2002 and 2003. The information from the studies, which are based on telephone interviews of metropolitan area residents, is used by Mn/DOT for planning, implementing, and operating different transportation management tools. Information on driving characteristics, driving behavior, and daily commute patterns is also collected during the interviews.
The objectives of the Perception Tracking Study are to measure over time the traveling public's awareness of the various traffic management tools, usage of these tools, and perceived effectiveness and value of the tools. The exact traffic management tools included in each annual study vary. For the 2006 study, two en-route tools – freeway entrance ramp meters and the FIRST program – and four communication tools – overhead DMS, traffic radio broadcasts on KBEM, traffic information on the internet, and the 511 information system – were included in the interviews.
A total of 600 telephone interviews were completed in March through April 2006, using a random digital dialing sample. This sampling technique includes unlisted telephone numbers to ensure that the results are representative of the metropolitan calling area. For the 600 interviews, the sampling error is +/- 4.0 percent at the 95 percent confidence level. Analyzing the results in smaller subgroup results in a higher error, however. The statistical tests of significance were conducted at the 95 percent +/- 5.0 percent level.
Many of the traffic management tools and related questions included in the annual interviews conducted for the Perception Tracking Study are relevant to the Minnesota UPA National Evaluation. As discussed in the next sections, perceptions related to the use of overhead DMS is of benefit for establishing a baseline for evaluating the UPA real-time traffic and transit DMS. Including questions on the DMS in future surveys will assist in the post-deployment analysis. Information is obtained on the freeway the interviewee normally travels, allowing the responses to be examined for I-35W and other facilities.
13.2 Traffic Management Tools and Interview Questions
As note previously, the traffic management tools included in the interviews for the Perception Tracking Study vary each year. These changes reflect the introduction of new technologies and management tools, as well as phasing out technologies and approaches. The changes also reflect a need to focus on Mn/DOT priorities each year. Table 13.1 presents the different traffic management tools and the number of years they have been included in the interviews.
Information from previous Perception Tracking Studies on the FIRST service, overhead DMS, express lanes, and park-and-ride lots is of interest in the National Evaluation of the Minnesota UPA projects. Information on driving characteristics, driving behavior, and daily commute patterns is also of interest.
Table 13-1. Traffic Management Tools Included in Perception Tracking Studies
| Traffic Management Tool |
Number of Years in Interviews |
| Highway Helper |
3 |
| FIRST |
3 |
| Metered Ramps |
9 |
| Overhead DMS |
8 |
| Express Lanes |
8 |
| By-Pass Lanes |
6 |
| Park-and-Ride Lots |
3 |
| KBEM Radio |
9 |
| Paragon Cable TV |
1 |
| Cable TV Broadcasts |
2 |
| KVBM TV |
3 |
| Internet Traffic Information |
8 |
| Traffic Telephone |
3 |
| 511 Service |
3 |
Examples of the questions related to the overhead DMS included in the 2007 interviews are presented below. The prompts from the interviewers are not included in the questions.
The first one I'd like to ask you about is overhead electronic message signs. These are electronic signs located over the freeway, alerting drivers of accidents or problems ahead.
| Section |
Question |
| P13a. |
Have you ever seen or heard of any of these signs?
Yes ( )
No ( )
|
| P13b. |
Have you ever seen a message displayed on any of them?
Yes ( )
No ( )
|
| P13c. |
How would you rate overhead electronic message signs as a tool to manage traffic? |
 |
Poor tool to
manage traffic |
|
|
|
|
|
|
|
|
Excellent tool to
manage traffic |
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
| Section |
Question |
| Q71a. |
How often, if at all, do you see travel time information posted on overhead electronic message signs? Would you say you see travel time information posted…?
Every weekday
Two or more times a week
Once a week
Two or more times a month
Once a month
Less than once a month
Never
Don't know
|
| Q71a1. |
How often do you believe you use the travel time messages to make a decision to either stay on your usual route or change your route?
Almost always
Sometimes
Rarely, or
Never
Don't know
|
| Q71b. |
How often, if at all, do you take an alternate route because a travel time message on an overhead electronic message sign showed a longer time than your usual time for a trip?
Almost always
Sometimes
Rarely, or
Never
Don't know
|
| Q71c. |
Would you say the posted travel times on the overhead electronic message signs are…? |
|
Never accurate |
|
|
|
|
|
|
|
|
Always accurate |
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
| Q71d. |
Would you say the posted travel times on the overhead electronic message signs are…? |
|
Poor idea |
|
|
|
|
|
|
|
|
Excellent idea |
|
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
13.3 Future Perception Tracking Studies
Mn/DOT personnel have indicated that the perception tracking studies should be continued in the future, although funding has not been totally secured. As a result, the interviews may be conducted every two years, rather than every year. Mn/DOT personnel have further indicated that including questions related to the real-time traffic and transit travel time DMS in the I-35W corridor should be possible. Additional questions related to the HOT lanes on I-35W and I-394 may also be possible, although it is less certain than the DMS questions. Possible questions related to the DMS are presented below. These questions, which are the same as those included in the focus groups discussed in Section 4.0 and the transit on-board surveys described in Section 5.0., are provided as examples.
| # |
Question |
| 1. |
Have you noticed the signs along I-35W displaying real-time transit and traffic information?
_____ Yes
_____ No
|
| 2. |
Is the information easy to understand?
_____ Yes
_____ No
_____ Don't look at the signs
|
| 3. |
Do you think the travel times presented are accurate?
_____ Yes
_____ No
_____ Don't look at the signs
|
| 4. |
Did the information on the signs influence you to start riding the bus?
_____ Yes
_____ No
|
| 5. |
Were you aware of the park-and-ride lots and bus services in the corridor prior to installation of the signs?
_____ Yes
_____ No
|
| 6. |
Do you have any suggestions on how the signs could be improved?
|
13.4 Analysis Method
Mn/DOT and their market research contractor conduct the perception tracking studies, including the interviews. The results are documented in a report, which presents both the current responses and comparisons with previous responses. Members of the Battelle team will examine the results from interview questions related to the real-time traffic and transit information DMS, any other UPA projects, and general trends related to perceptions of traffic conditions and travel behavior. The results for individuals identifying I-35W as their major travel corridor will be examined.
13.5 Schedule and Responsibilities
Mn/DOT typically conducts the perception tracking study in the spring of the year. Members of the Battelle team will work with Mn/DOT to include questions on the real-time traffic and transit information DMS in the 2010 and 2011 surveys. Conducting the interviews in either 2010 or 2011 would benefit the UPA national evaluation. Including questions on the HOT lanes will also be explored. Members of the Battelle team with work with Mn/DOT personnel to obtain copies of the final reports and detailed surveys results, and will use the results in the final evaluation report.
