There are several circumstances in which drivers may be ticketed for illegally blocking or impeding traffic by driving too slowly or failing to yield to a long line of vehicles behind them. Let's look briefly at the most common.

Driving Too Slowly in Left Lane

Your state's law will say something like:

In plain English, this law means if you're poking along, you had better be in the right-hand or slow lane unless you're preparing to turn left.

The elements of the violation are:

1. You drove at a speed "less than the normal speed of traffic," and
2. You didn't drive "as close as practicable to the right-hand edge or curb."

Of course, if you read your statute carefully, you'll likely find that there is one big exception to this move-to-the-right-if-you-are-driving-slowly requirement. As long as it is permitted, you have the right to move to the left to pass an even slower vehicle, even if doing so means you are briefly driving slower than the normal speed in that lane. For example, if you are driving 35 mph in a 45-mph zone and there is a farm tractor, an oversize motor home, or some other slow vehicle in the right lane doing 20 mph, it's okay for you to be one lane to the left to pass it.

The best way to defend against this ticket is to prove:

• In an "absolute" speed limit state (see Fight Your Speeding Ticket: What is the Law?) you were traveling at the posted speed limit.
• You were preparing to make a left turn (if true).
• You were passing even slower-moving traffic to the left and were prepared to return to the slow lane as soon as it was safe.
• Your speed, although below the posted limit, was the only safe speed for that road under the conditions you were driving through, which could include rain, wind, darkness, or other dangerous conditions.
• You were blocking the traffic behind you only because, in fact, it wasn't safe to go any faster.

In court, the officer must testify only that you were driving below the speed limit, or, in a "presumed" speed limit state, at a speed slower than other safe-driving traffic.

It is then up to you to show a legal excuse for your action—for example, road conditions required that you slow down, or the glare from a reflected window prevented you from seeing clearly.

Impeding Traffic

This offense is similar to driving too slowly in the left lane. The difference is that you can be charged with the offense even if you're in the curb lane or the only lane on a one-lane road.

A typical impeding traffic law says:

The elements of this violation are:

1. You drove on a highway at a speed less than the "normal and reasonable" speed of traffic.
2. Your reduced speed was not made necessary by safe operation or a grade, and
3. You were not speeding.

The success or failure of your defense will normally pivot on whether you can convince the judge that your view of events was more reasonable than that of the officer's. Your best defense is to show that your slow speed was reasonable because of road, weather, or traffic conditions. An officer trying to make this one stick will likely testify that you were driving below the speed limit and holding up a long line of frustrated, finger-gesturing, horn-honking drivers. The law will excuse your slow driving if you can show:

• You were traveling at the posted speed limit, or safely above it in a "presumed" speed-limit state, or
• You were driving slower than the posted speed, but lower speed was "necessary for safe operation" of your vehicle.

During cross-examination ask the officer, "How fast was traffic moving when I was stopped?" If the officer claims not to remember (but can remember that cars were trying to get past you), you should prevail if you can testify that you were driving at the speed limit while the cars trying to pass you were attempting to violate the posted limit.

But if you were driving much under the posted limit, this first defense won't work. In this situation, be prepared to testify and document—with photos or diagrams—that poor road conditions, bad weather, steep grades, or sharp curves made a higher speed unsafe. Although personal reasons normally won't help, this is one circumstance where I have occasionally seen a judge side with a motorist who tells a good story. If, for example, you were carrying 12 dozen cartons of raw eggs to an Easter celebration or moving your grandmother's 100-year-old dishes over a poorly paved road, it won't hurt to work it in to your testimony.

Rough pavement can be a reason to go slowly. Speed limits are normally posted based on an assessment of how fast it is safe to go on a particular road. Occasionally, however, conditions change for the worse after the speed limit is posted. This is particularly likely if construction or heavy wear has degraded the road surface. So if the pavement was in bad shape, make sure you document it with photographs and argue that it was unsafe to go faster than your speed.

Failing to Use "Turnouts"

A turnout is usually a patch of pavement on the right side of the road where slow drivers can pull off the road to let faster drivers go past. If you're driving slowly and there are a whole lot of drivers behind you wanting to go faster, you normally have a legal duty to pull over and let them go by.

Here, a typical state law reads like this:

The elements of this violation include:

1. You were driving a "slow-moving vehicle," meaning you were driving slower "than the normal flow of traffic" at the time.
2. You were on a highway with two lanes, one in each direction.
3. There were at least five other vehicles behind yours that all slowed down because of you (this number can vary from state to state), and
4. You failed to pull over at a marked "turnout" or other widened area to the right where you could safely pull over.

Driving slowly because of safety concerns, such as a degraded pavement, is not a defense to this charge, since you could still have used the turnout. Your only available defense is normally that, for some good reason, you were unable to pull over safely to let the other traffic past. For example, you may not have been able to use the turnout because you were pulling a trailer, trying to avoid a hole in the road, or afraid of slipping on snow or ice.