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Surveying employees is a required part of every Commute Trip Reduction program. Employers must conduct a survey every two years to evaluate their program's success at reducing drive-alone commute trips. This page contains resources for implementing a survey. If you have any questions or need additional assistance, please contact us.

How to conduct a survey

You will be notified at least 45 days in advance of your survey period, which runs for one month. The month your survey occurs in is determined by your location, but you will have the option to select the start date on your Survey Response Form. Contact your Employer Transportation Representative if you have any questions or concerns about the survey.

  1. Determine whom you will survey.
    • You must survey every employee at a worksite who meets the definition of a "CTR affected employee," or you can survey all employees. A CTR-affected employee fits all four criteria:
      • Works at least 35 hours in a week.
      • Begins work at a single worksite between 6 and 9 AM.
      • Works on two or more weekdays each week.
      • Their position is intended to last for at least 12 continuous months.
  2. Decide whether you will use the online or paper survey format.
  3. Complete the Survey Response Form you will receive from your ETR about 45 days prior to the start of your survey month.
    • The form contains the information required to set up your survey and gives you an opportunity to share any recent changes to your CTR program.
  4. Distribute the survey instrument (online or paper) to your employees.
    • The minimum response rate is 50%.
    • Worksites should strive to collect completed surveys from at least 70% of surveyed employees. A survey response rate of at least 50% is required to be included in WSDOT's measurement database. If you do not reach a 50% response rate, you will be required to survey again.
  5. Keep the survey open for two weeks.
    • While your survey period runs an entire month, it is generally best to survey employees during a single, week-long period. The survey asks respondents about their commute "last week" so avoid conducting your survey the week following a holiday.
    • If you conducted an online survey, it will close after two weeks. Contact your ETR if you need an extension in order to meet your response rate goal.
  6. If you conducted a paper survey, collect completed surveys from your employees.
    • Email your ETR to arrange for courier pickup. Review the Paper Survey Pick-up instructions for additional information. Remember to complete your Employer ID sheet and include it with your surveys.
  7. Review your survey results report, which will be sent to you three or four weeks after the survey responses have been collected.

What the survey measures

Trip reduction surveys measure progress by looking at Non-Dive Alone Trips (NDAT) and Vehicle Miles Traveled (VMT). Changes in these numbers are measured surveying employees every two years.


Each jurisdiction sets CTR targets for companies located within the city boundaries. Companies must make progress towards their targets at every biennial survey. For example, the baseline survey for Fancy Hats Inc. found their NDAT was 23% and their average VMT was 11 miles. The jurisdiction gave Fancy Hats Inc. the goal of increasing their NDAT rate to 29% and/or reducing their VMT to 8.5 miles. Fancy Hats then designed a transportation program to meet those goals and evaluated the success of their program via the biennial survey.

After each biennial survey your company or organization will receive one of the following three ratings:

Goal met

You have met your goal! Keep up the great work.

Making progress

Your NDAT or VMT rates show you are moving in the right direction. You should strengthen your CTR program.

No progress

You are not making progress toward your target goals. Your ETR will work collaboratively with you to identify program enhancements that will help you as an employer make progress toward your NDAT and VMT targets.

Setting up your online survey

Comparing your options

When distributing an online survey, you can choose how your employees will log into the survey site. Use the table below to help decide which method is right for you.

Method Description Advantage Disadvantage
Domain name(s)

Anyone with an email account matching a certain domain can fill out the survey.

  • Easy to set up.
  • No way to track non-respondents.
  • Multi site companies run the risk of employees selecting the incorrect worksite at login.
Upload email list

Upload email addresses for each person to be surveyed. Each employee uses his or her own email address to log in to the survey site.

  • Greater control over who may access online survey
  • You can track and email people who have not yet completed survey. This allows you to send an email reminder to individuals who have not yet completed the survey.
  • More time consuming to set up. You must compile an email list of the individuals to be surveyed

Supplemental questions

The online survey includes the option of choosing from a library of supplemental questions that may provide additional insight into your program’s effectiveness. Results from these questions will be sent in a separate data file from your regular CTR survey report. These questions must be set up by the ETC in advance of the survey start date.

Survey management

To manage your online survey, log into the ETC site. To see an example of the online survey tools available, log in with these credentials:

Password: etctest1

Once you log in, click on the CTR Survey tab at the top of the page. If you choose the online survey, you will receive your own login information.

Paper and foreign language surveys

Collecting surveys by paper

For some worksites, distributing and collecting paper surveys may be a better approach to reaching your goal response rates. If you choose to survey with the paper format, King County Employer Services will send you hard copies of the survey. During your survey cycle, Employer Services will send you a notification with an attached Survey Response Form for review and return with changes.

See below for resources to help with a successful paper survey:

Surveys in non-English languages

Washington State offers translations of the first five questions of the CTR survey, which are the required questions that affect your survey results. These translation guides are a way for non-English-speaking employees to complete the survey (online or paper). If your worksite requires large numbers of non-English survey responses, contact your Employer Transportation Representative for distribution and collection assistance.

Steps when using paper surveys:
  1. For those that speak a language other than English, distribute the English CTR survey questionnaire along with the foreign language equivalent.
  2. Provide direction to complete the English CTR survey questionnaire, using the translated equivalent as a guide.
  3. After you have collected the surveys, make sure you are only returning the English CTR survey questionnaire. The foreign language equivalents cannot be scanned and calculated like the English-language versions.
Steps when using online surveys:
  1. Distribute the foreign language translation guides to employees as needed and have them complete the translation paper guide in place of the survey.
  2. Collect the foreign language translation guides and manually enter them into the online survey.

Counting vehicle miles traveled and non-drive-alone trips

Calculating vehicle miles traveled

The vehicle miles traveled (VMT) calculation combines the number of people who share a trip with the length of the one-way commute trip. The more people who share the commuting vehicle, the lower the VMT total.

The calculation formula is:

(Trips per person × miles per trip) = VMT

Trips per person is based on the travel mode and number of people in a vehicle. Show table

# of Occupants Trips per person
Driving alone (includes one-person motorcycle and drive-on ferry) 1
Two-person carpool/vanpool 0.5
Three-person carpool/vanpool 0.33
Four-person carpool/vanpool 0.25
Five-person carpool/vanpool 0.2
Six-person carpool/vanpool 0.16
Seven or more vanpool 0
Bus, train or walk-on ferry 0
Teleworking or compressed work week 0
Non-motorized (bicycling, walking) 0


Jessica commutes to work five days each week. She drives alone three days and carpools with one friend the other two days each week. Her one-way trip is 10 miles.

That calculates to:

  • Monday drove alone (Adjusted trips = 1)
  • Tuesday drove alone (Adjusted trips = 1)
  • Wednesday drove alone (Adjusted trips = 1)
  • Thursday carpooled (Adjusted trips = 0.5)
  • Friday carpooled (Adjusted trips = 0.5)

The total adjusted trips is 4.

Take the total adjusted trips and divide by 5 potential trips. The result will equal the Trips per person—such as, 4 ÷ 5 = 0.8 Trips per person.

Final result: (0.8 × 10) = 8 VMT

Calculating non-drive-alone trips

The non-drive-alone trips (NDAT) calculation measures what percentage of potential commute trips are made in a manner other than by one person driving alone.

The calculation formula is:

(non-drive-alone trips ÷ potential trips) = NDAT


Joe works five days a week and drives with another person two of those days. Joe’s NDAT can be calculated as follows:

Take the 2 non-drive-alone trips and divide by 5 potential trips. The NDAT value is 0.4 (or 40%).

Employee exemptions and equivalent data

What is an employee exemption?

A group of employees may be exempted from a worksite’s CTR survey if they fall into either of the following two categories:

  1. Employees who work variable shifts throughout the year. To qualify under this situation the employee must:
    1. Work variable shifts during the year, some of which begin between 6 AM and 9 AM and some of which do not, and
    2. Do not rotate from one shift to another with the same group of people. (Reasoning: If a significant number of employees rotate shifts with the same group, they still have a consistent pool of potential carpool and vanpool partners.)
  2. Employees who are required to drive their own vehicles to work because of the type of work they do or their work schedule. To qualify under this situation the employee must:
    1. Be required to drive a vehicle to work and use it during the workday for work purposes, and
    2. Cannot use the vehicle to carpool or vanpool when commuting. This must be a condition of their hiring and specified in their job description.

Employee exemptions must be requested and approved prior to each survey process.

Pre-approved equivalent data

In some circumstances the CTR Task Force Guidelines allow employers to substitute "equivalent” data for information collected through the CTR survey. To be considered equivalent and useful for measurement of VMT and NDAT reductions, the data must provide information on employees’ actual commute mode usage during the measured week. This information in turn must be linked to employee status and work schedules. These data characteristics are necessary for calculating worksite NDAT and VMT and for evaluating program elements.

Please contact your ETR if you have questions. The local jurisdiction, in consultation with the WSDOT TDM office, will evaluate whether the equivalency of any data submitted by an employer can be accepted in lieu of the state survey.

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