Frequently Asked Questions

What is slugging?

Slugging is a unique form of carpooling found in many regions including Washington, D.C., San Francisco, Houston, and Pittsburgh. Sometimes referred to as "instant carpooling" or "casual carpooling," drivers will pick up riders (also known as “slugs”) at slug lines to use HOV/Express lanes without paying tolls. It’s free, fast, and has been the norm for Northern Virginia commuters along I-95 for decades.

Slugging is a well-organized, community-driven system with its own rules and etiquette. It operates at designated pickup and drop-off locations during specific times of day. Because there are no stops along the way, slugging is typically faster than transit or general purpose lanes along I-66. And, if you do not find a slugging match, convenient transit alternatives are always available. You will quickly discover that slugging is one of the most efficient and cost-effective commuting options for your work commute!

What are the benefits of slugging?

Slugging can help reduce commuting costs, make better use of HOV lanes, reduce traffic congestion, and connect commuters with others traveling the same route.

How do slug lines work?

Slug lines are designated pickup and drop-off locations where drivers and riders meet to form carpools without advance reservations. Drivers pull up to the slug line and either display a sign or announce their destination. Riders traveling to that destination join the vehicle, and the group travels together. This process is often called "instant carpooling" because it requires no scheduling or commitments.

Most slug lines operate on a first-come, first-served basis, with riders lining up according to their destination and available drivers selecting passengers from the front of the line. Slugging works because it benefits both drivers and riders—drivers gain passengers needed to meet HOV-3+ requirements, while riders receive a free ride.

To get started:

1. Find your slug line on the Slug Lines page.
2. Identify the pickup and drop-off locations for your trip.
3. Download and print destination signs, if needed.
4. Drivers using the I-66 Express Lanes should ensure they have an E‑ZPass Flex transponder and meet HOV-3+ requirements.
5. Go to the appropriate slug line, confirm the destination, and enjoy the ride.

Challenge Tip: If you're trying a slug line for the first time, consider allowing yourself extra time and having a backup travel option available until you become familiar with typical demand patterns.

Community Tip: Join the community and connect with fellow slugs through these Facebook groups:

• Slug I‑66 Facebook Group (I‑66 Slugging Challenge participants and active I‑66 slugs)
• I‑66 Sluglines Facebook Group

Is slugging safe?

Slugging has been used by commuters in the Washington, D.C. region for decades and is built around a strong culture of courtesy, trust, and shared expectations. Like any shared transportation option, participants should use good judgment, follow established slugging etiquette, and only participate when comfortable.

One factor that helps support a safe and reliable experience is the "rule of 3s." Traditionally, vehicles travel with at least three occupants to qualify for HOV requirements. This means drivers and riders typically travel in groups rather than one-on-one, providing an added level of comfort for many participants.

Just as important is the slugging community itself. Slugging works because commuters look out for one another, follow established norms, and share a common goal of getting everyone where they need to go efficiently. Many commuters ride the same routes regularly, creating a familiar and welcoming environment for both new and experienced participants.

Slugging Tip: Slugging is a community-driven transportation option. Join the conversation, ask questions, share updates, and connect with fellow drivers and riders through these Facebook groups:

• Slug I‑66 Facebook Group
• I‑66 Sluglines Facebook Group

Does it cost anything to slug?

Traditionally, slugging is a free ridesharing arrangement. Drivers receive the benefit of toll-free access to the I-66 Express Lanes by meeting the HOV-3+ requirement, while riders receive transportation without paying a fare.

Drivers who wish to travel toll-free on the I‑66 Express Lanes must have an E‑ZPass Flex transponder and meet all applicable HOV requirements, including having three or more occupants in the vehicle and setting the transponder to HOV ON before entering the Express Lanes. Drivers are responsible for obtaining and maintaining an E‑ZPass Flex account and transponder and for complying with all applicable HOV rules.

Do I need to schedule a ride in advance?

No. One of the defining features of slugging is that it does not require reservations or prearranged carpools. Slugging is often described as "instant carpooling" where drivers and riders simply meet at designated pickup locations and travel together when a match is available.

Unlike traditional carpools, you don't need to coordinate schedules, exchange contact information, or commit to riding with the same people every day. Just show up at a slug line, join the queue, and ride when a driver or rider headed to your destination is available.

This flexibility is what has made slugging a popular commuter option in the region for decades.

How do I know which slug line to use?

Slug lines are organized by destination. Visit our Slug Lines page to find pickup and drop-off locations and identify the slug line that best matches your commute. We recommend reviewing the locations before your first trip.

What should I do when I arrive at a slug line?

Look for the queue associated with your destination and join the line. Drivers will announce or display their destination, and riders will board in the order established by local slugging etiquette.

How long should I wait before I leave?

There is no set waiting time. Ultimately, it's up to you to decide how long you're comfortable waiting for a ride or passenger. If you don't find a match, consider checking community resources such as local Facebook groups or other commuter forums, where slugs often share information, ask questions, and discuss travel patterns. The more drivers and riders who participate, the more reliable slugging becomes for everyone.

Slugging Tip: If you're trying a slug line for the first time, consider allowing yourself extra time and having a backup travel option available until you become familiar with typical demand patterns. Local slugging communities and online discussion groups can also be a helpful resource for learning what to expect. You can connect with other drivers and riders through the Slug I‑66 Facebook Group and the I‑66 Sluglines Facebook Group.

What if there isn't a driver or rider for me?

Building a successful slug line takes participation from both drivers and riders, and the purpose of the Challenge is to help create the critical mass needed for slugging to grow along the I-66 corridor.

Connect with a slugging community! Because slugging is a self-organized and community-driven system, individual commuters often take initiative to form groups – either centered around a specific slug line location or serving the broader slugging community. These groups may exist on platforms like Facebook, WhatsApp, or through email distribution lists. Members occasionally use them to request rides home when working late or to proactively coordinate travel plans with others.

Slugging Tip: Slugging is a community-driven transportation option. Join the conversation, ask questions, share updates, and connect with fellow drivers and riders through these Facebook groups:

• Slug I‑66 Facebook Group
• I‑66 Sluglines Facebook Group

Will more slug lines be added in the future?

That's up to the community. Slugging has always evolved through the efforts of commuters themselves. As more drivers and riders participate, new routes and pickup locations may naturally emerge where demand exists. The I-66 Slugging Challenge is intended to help bring people together and support that growth.

How do I prepare for slugging as a driver?

• Set Up Your E-ZPass Flex for HOV-3+ Travel: It is important to note that drivers looking to pick up slugs and enjoy toll free travel must have an E-ZPass Flex mounted securely to the windshield inside the car. The E-ZPass Flex must be switched to HOV ON mode once 3 or more passengers are in the car in order to use the Express Lanes toll-free. Need an E-ZPass Flex transponder? Order one or pick up an E-ZPass Flex at participating retailers and select DMV locations throughout Virginia.
• Pick Your Slug Lines: Pick the slug line locations you plan to use for your morning and afternoon commutes and familiarize yourself with the designated pickup/drop-off areas at each location. Consider printing a sign with your destination to hold or display on your dashboard (remember to identify both your morning and afternoon commute destinations). Download and print destination signs from the Participant Toolkit here.
• Wait for Slugs: Arrive at the slug line location and wait for your riders. If there is a line of vehicles, pull in at the end of the line and wait. Plan to either display your sign, or roll down your passenger window and call out your destination to the riders.
• Commute: Once there are 3 or more people in your vehicle, switch your E-ZPass Flex to HOV ON mode (you should hear a beep when you do this). Head to the Express Lanes and enjoy zipping past traffic!

How do I prepare for slugging as a rider?

• Pick Your Slug Lines: Pick the slug line locations where you plan to catch a ride for your morning and afternoon commutes and familiarize yourself with the designated pickup/drop-off areas at each location.
• Plan Your Backup Travel Options: One of the benefits of slugging is its flexibility. Plan your morning and afternoon backup travel options using a combination of buses, trains, rideshare, or personal ride (e.g., picked up by a spouse) to ensure you have reliable and flexible travel options, particularly on your return trip after work.
• Sign Up for Guaranteed Ride Home (GRH): Before you start slugging, consider enrolling in Commuter Connections' Guaranteed Ride Home program. GRH may provide a backup ride home for eligible commuters in certain situations, giving you added peace of mind while trying new commute options. Learn more and enroll.
• Wait for Drivers: Arrive at the slug line location and get in line to wait for a driver. When a vehicle pulls up, the driver will either have a sign or will call out their destination. Be sure to confirm the destination with the driver.
• Commute: Once you are in the vehicle, sit back, relax, and enjoy your ride!

I’m a driver. Do I need an E-ZPass Flex transponder?

If you plan to use the I‑66 Express Lanes while picking up slugs and want to travel toll-free under the HOV-3+ requirement, you must have an E‑ZPass Flex transponder. Make sure it is properly mounted on your windshield inside your vehicle and switched to HOV ON mode before entering the Express Lanes whenever there are three or more occupants in the vehicle.

If fewer than three people are in the vehicle, the transponder must be set to HOV OFF mode, and applicable tolls will be charged.

Drivers are responsible for ensuring they meet all HOV eligibility requirements and for using their E‑ZPass Flex transponder correctly.

Slugging Tip: Need an E-ZPass? Order one or purchase an E-ZPass On-the-Go transponder at participating retailers and select DMV locations throughout Virginia.

What if I drive on some days and ride on others?

One of the key benefits of slugging is flexibility. Drivers and riders can easily swap roles for the day if they have no preference for their commute. A driver waiting in a line of cars may notice too few riders at the slug line and opt to park their car in the park-and-ride lot and assume the role of a rider. A rider arriving at the park-and-ride lot may notice a long line of riders and opt to assume the role of a driver.

For the I-66 Slugging Challenge, you can participate as a driver, a rider, or both. Many commuters choose whichever option works best for them on a given day. Eligible trips count toward the Challenge regardless of whether you were the driver or rider.

What if I can't get back home?

If you expect to commute as a rider, you should know your backup transportation options in the event you are unable to match with a driver, particularly on your return trip from work. Plan to use buses, Metro, trains, rideshare (e.g. Uber, Lyft), or a personal ride (e.g., picked up by a partner or friend) to ensure you have reliable and flexible travel options.

We also encourage riders to enroll in Commuter Connections' Guaranteed Ride Home (GRH) program, which may provide a backup transportation option for eligible commuters in certain situations. You can find more information about Commuter Connections’ Guaranteed Ride Home program here.

What are my backup commuting options?

Slugging is designed to be flexible, and many commuters use a combination of travel options depending on their schedule and destination. To help you plan ahead, we've included information about available bus and transit alternatives for each route on the Slug Lines page of this website.

We also encourage riders to enroll in the Commuter Connections Guaranteed Ride Home (GRH) program, which may provide a backup ride home for eligible commuters in certain situations.

Challenge Tip: If you're trying a slug line for the first time, consider allowing yourself extra time and having a backup travel option available until you become familiar with typical demand patterns.

Slugging Tip: Join the community and connect with fellow slugs through these Facebook groups:

• Slug I‑66 Facebook Group
• I‑66 Sluglines Facebook Group

Is there slugging etiquette I should know?

Slugging has been built by commuters over several decades and is supported by a set of informal etiquette guidelines that help keep rides safe, efficient, and enjoyable. Topics include things like lining up for rides, choosing seats, conversation during the ride, and general courtesy between drivers and riders.

For a summary of common slugging etiquette, visit Slugging Etiquette. The guidance is based on information preserved from the former slug-lines.com website, which served as a long-standing resource for the region's slugging community (used with permission).

Do I sit in the front or back seat?

The first rider in line also gets to choose the front or back seat. As always, wear your seatbelt and be courteous to fellow riders.

What is the I-66 Slugging Challenge?

The I-66 Slugging Challenge is a 66-day event running from September 14 through November 20, 2026, that encourages commuters to try slugging along the I-66 corridor. Register, log eligible trips, and earn an entry into a weekly drawing for a $100 gift card every time you slug. Most importantly, you'll be helping build a stronger, more reliable slugging community.

When do I have to register for the I-66 Slugging Challenge by?

We encourage you to register as soon as possible. Early registration helps us build the critical mass of drivers and riders needed for successful slug lines. If there are not enough participants for your preferred slug line, travel time, or destination, we will notify you. The earlier you register, the better we can support ride matching and help establish a thriving slugging community.

Commuters may register after the Challenge starts and still participate. Registering early gives you access to Challenge updates, resources, and information before Day 1.

How do I log trips and qualify for prizes?

To participate in prize drawings, register for the Challenge and log your eligible slugging trips using the CommuterCash app. Each logged trip earns entries toward Challenge prizes, subject to the Official Rules.

What does "critical mass" mean?

Critical mass is the point at which enough drivers and riders regularly participate that slugging becomes reliable and self-sustaining. The more people who join, the easier it becomes for everyone to find a ride and keep the system working smoothly. Building that critical mass is one of the primary goals of the I-66 Slugging Challenge. More participants typically mean shorter waits, more reliable rides, and more opportunities for new slug lines to emerge.

Where did the word “slug” come from?

The term "slug" itself did not derive from the terrestrial gastropod mollusk you might spot in a garden. Instead, it appears to have originated as a derogatory term created by bus operators, who were on the lookout for riders using counterfeit or fake coins (also known as slugs) for bus fare.

When slugging was in its infancy, riders looking for a driver would wait at bus stops. Bus operators, thinking they were waiting for the bus, would stop for them only to be waved off. This frustrated many bus operators. As this began to happen more frequently, bus operators began recognizing the real bus riders from the “fakes” ones. Because the people weren’t really waiting for the bus, operators began to refer to them as "slugs." This explanation seems to make sense because these people weren’t real bus riders, or even real carpoolers in the usual sense of the word. They were, just as the name implies, counterfeit riders or slugs. Hence, the term was born.

Over time, more attractive and politically correct terms – such as "instant carpooler," "hitchhike commuter," and "casual carpooler" – have emerged, but the tradition of the term “slug” has outlived these alternatives.