Why Zipper Merges Are Risky For Pennsylvania Drivers

According to data released by the Commonwealth of Pennsylvania, 13 reportable traffic crashes occurred every hour in the state in 2024. With 1 in 54 Pennsylvanians falling victim to traffic collisions on local roadways, it’s no surprise the Commonwealth has continued to take steps to enhance safety and reduce the incidence of preventable crashes. One of the well-intended solutions PA has adopted to streamline the driving experience for motorists across the state is a traffic protocol known as the “zipper merge.

The idea is simple in theory: when a lane is about to end, drivers should wait to change lanes until the last possible merge point and then take turns with drivers in the other lane to merge safely and seamlessly. While this strategy is meant to promote efficiency and reduce congestion, it often leads to confusion, frustration, and, in many cases, serious car accidents. Let’s take a closer look at why the zipper merge doesn’t always work the way it’s supposed to and discuss who can be considered liable for accidents involving zipper merging.

What is a zipper merge?

A zipper merge is a traffic flow method recommended when two lanes of traffic are reduced to one. Most commonly, zipper merging is adopted during construction or in response to an accident, flash flooding or other temporary obstruction. When any of these situations results in a lane closure, drivers are encouraged to use both lanes up until the point of the merge rather than attempting to merge far in advance of the closure.

When done correctly, this method is meant to reduce bottlenecks, minimize road rage and reduce the amount of time spent in traffic jams related to lane closures. While zipper merging sounds good in theory, it often leads to unintended consequences on Pennsylvania roads when put into practice.

When the zipper merge doesn’t always work

While zipper merging might make sense on paper, it’s a little harder to execute properly in real life. While some states require zipper merging by law, Pennsylvania recommends rather than mandates it due to some of the recognized challenges it presents on local roadways.

Here are a few reasons why the zipper merge doesn’t work for Pennsylvania drivers:

Conflicting expectations

Many drivers are taught to merge early out of courtesy, believing that those who use the full length of the closing lane are “cutting in line.” This stands in stark opposition to the tenets of zipper merging, which is a required part of drivers’ education in many states. These conflicting protocols can cause confusion on Pennsylvania roadways and may even contribute to road rage incidents.

Aggressive driving

In fast-moving traffic, attempting a last-minute merge can increase the risk of side-swipe or rear-end collisions. During high-stress commuting hours, drivers may be more prone to engaging in dangerous driving behaviors to prevent vehicles from merging “at the last minute.” These aggressive driving practices can significantly increase the chances of collisions and other traffic infractions with potentially dangerous consequences.

Poor signage

Zipper merges only work when drivers know what’s expected of them. If there is no signage clearly designating the appropriate merging protocols, drivers tend to take an “every man for himself” approach to merging in response to lane closures. While Pennsylvania lacks a formal zipper merge law, PennDOT has promoted zipper merging through signage in construction zones. However, such signs are not used universally across all lane closures, and plenty of other lane closures occur too quickly to give PennDOT enough time to erect sufficient signage.

Unequal vehicle sizes

Trucks, buses and other large vehicles tend to struggle to merge as smoothly as smaller cars, making a last-minute zipper merge less efficient and potentially hazardous. In 2021, Pennsylvania reported having over 54,000 registered buses across the Commonwealth — the 5th highest number in the country. With so many large vehicles on the road, a poorly timed or forced merge can lead to accidents and delays that can start a domino effect for neighboring drivers.

Distracted drivers

In 2023, the Commonwealth of Pennsylvania reported over 11,000 traffic accidents related to distracted driving. Zipper merging requires a particular combination of attention and coordination, as it requires drivers to work together to time and execute fast merges. If one driver is distracted – by their phone, GPS, etc. – it can throw off the timing of the entire merging process and even lead to serious accidents.

Does zipper merging cause accidents?

As we’ve discussed, zipper merging is intended to help enhance safety and minimize delays during lane closures. However, poorly executed zipper merges can cause far more problems than they solve and may result in accidents like:

• Side-swipe collisions when two vehicles try to merge at the same time
• Rear-end accidents caused by sudden braking or hesitation
• Road rage incidents leading to aggressive driving or intentional blockages
• Multi-car pileups in high-speed or high-volume traffic areas
• Pedestrian or work zone injuries when vehicles veer off course or swerve

These types of crashes can result in serious injuries ranging from whiplash to traumatic brain injuries and can have particularly devastating consequences in congested, high-speed merge zones.

Who is considered liable for zipper merge accidents

Zipper merge accidents often result in “he said, she said” disputes with both drivers attempting to claim the other failed to merge properly. These situations can pose unique challenges in terms of determining liability, and insurance companies often try to minimize payouts by shifting blame.

Under Pennsylvania law, merging drivers are generally responsible for accidents that result from unsafe merging. However, drivers who are already established in traffic still have a responsibility to exercise care and caution and refrain from intentionally preventing another driver from merging ahead of a lane closure.

If a driver begins to merge at a time when it would generally be considered safe for them to do so and another driver unexpectedly speeds up or swerves into the merging vehicle, the non-merging driver may be considered at least partially liable for the collision.

Comparative negligence in the Commonwealth

Under the current law, drivers are expected to engage in safe driving practices and prioritize their own safety, as well as the safety of those around them. Subsequently, the Commonwealth of Pennsylvania uses a comparative negligence system when determining liability in personal injury and car accident cases. This means both drivers’ contributions to a crash will be assessed and any damages awarded to them in their case will be reduced commensurately with their level of fault.

For example, if a merging driver zipper merges too quickly and strikes another driver who was texting rather than watching the road, both drivers could be found partially responsible for the crash. If, let’s say, an insurance company or judge determines the texting driver was 20% responsible for the collision – that driver would have their final damage amount reduced by 20% to account for their level of fault. However, if their amount of fault exceeds the other driver or drivers’ share of liability, they cannot recover.

Working with a knowledgeable attorney can help level the playing field when determining fault for zipper merge-related accidents and push back against unsubstantiated claims of joint liability.

Looking ahead: How to make zipper merging safe, simple and speedy

As more states adopt formal guidance or legislation around zipper merging, it is entirely possible that Pennsylvania will follow suit. Until then, however, driver education and clear communication remain the best tools for promoting safe merging behavior and discouraging aggressive driving tactics.

Regardless of whether or not zipper merging becomes law, drivers will still need to exercise caution, courtesy and common sense when navigating lane closures and other traffic hazards. Failure to exercise reasonable care in these situations could open up drivers to claims of liability – particularly in cases that result in serious physical, mental and/or financial harm.

If you’ve been involved in a merging-related traffic accident in Pennsylvania, the experienced team at KBG Injury Law may be able to help you fight for the compensation you need to get back on your feet. Whether your accident occurred as the result of reckless behavior, poor signage or distracted driving, our compassionate team of car accident and personal injury lawyers can offer you the support you need to navigate the complex nature of merging-related cases.

No matter where you are in your legal journey, we would love the opportunity to help you negotiate with insurers, walk through settlement discussions and even build a comprehensive court case. Give us a call today or fill out our contact form to schedule a free case consultation, and our team will provide you with the information you need to move forward with comfort and confidence after your accident.