Speed limits aren't always black and white

Thursday, August 26, 2010; T16

Dear Dr. Gridlock:

I hope you might explain the perennially perplexing issue of speed limits, which universally never at all seem to be limits (per that definition).

In a rational world, the limit would be the uppermost allowable speed for any stretch of road. And to exceed that limit by even 1 mph would be a breach of law. This would be easy to understand and easy to teach to the general public.

Instead, nearly every domestic jurisdiction allows a leeway of up to 10 mph over the limit, beyond which one is then considered to have breached the law.

The only reasoning that I can cipher from this law enforcement curiosity is that it allows those in law enforcement to pull anyone over, for suspicion of any kind, should the driver's speed exceed the limit by even 1 mph. Essentially this enforcement habit lulls the general public into a degree of vulnerability, that law enforcement officials can then use to their advantage when they want to stop a suspect for investigation but otherwise have no legal justification to do so.

Rocky Semmes


DG: Driving 1 mph over the speed limit is a breach of the law. In the Washington region, a police officer can stop a driver any time for driving faster than the speed limit.

Clearly, that's not how most officers go about enforcing the speed laws. They use some discretion. But all the driver should need to know is what the speed limit sign says.

That is, unless the driver is in Maryland and passing through a speed camera zone. The General Assembly has trouble passing some very basic rules about driving, such as a requirement to stop before entering an intersection with a disabled traffic signal. It did, somewhat remarkably, pass a law that allows local jurisdictions and the State Highway Administration to place speed-enforcement cameras in certain areas.

But the law is written conservatively. A driver needs to be going at least 12 mph over the speed limit to get a $40 ticket from a speed camera. In the Intercounty Connector work zone on Interstate 95, where the speed limit is a generous 65 mph, that pegs the speed camera target at 77 mph.

The law also says that the speed cameras can be used in school zones only from 6 a.m. to 8 p.m. weekdays. The speed limit doesn't change during off-hours, only the jurisdiction's ability to enforce the law using the cameras. Even during the operating hours, a ticket is issued only when the car speeds at least 12 mph over the limit through the school zone.

The District also uses cameras but won't say what the threshold speed is to generate a ticket. I like that better. There's no official sanction for speeding the way there is in the Maryland law.

Fare gate slowdowns

The slight delay at the Metrorail fare gates caused by the SmarTrip reprogramming has a parallel in driving.

When cars are following each other too closely on the Capital Beltway, just one brake tap will create an accordion-like contraction in traffic that might stretch back a mile or more till the drivers spread out a bit.

When Metrorail riders are moving toward a fare gate with little room between them, the extra beat waiting for the orange barriers to open creates a similar contraction in the line.

We're trying to adjust.

Dear Dr. Gridlock:

I have a hint that might speed the time at fare gates a bit. If you use a SmarTrip card and have fairly good eyesight, just watch the green readout window at the fare gate. The readout changes from the previous rider who went through the gate, and it occurs faster than waiting for the gate to open. A rider can walk forward after the fare is registered and get to the orange gate just as it opens.

Joe Poduska


DG: I've tried to follow this suggestion by staring at the readout, but so far, my reflexes haven't propelled me through the fare gates any faster.

Besides, my main concern isn't to get through the gate faster. It's to stop the following rider from squishing me against the fare gate barrier. So I find myself coming to a stop at the entrance to the gate and pressing my SmarTrip card against the circular reader.

That doesn't make the barrier open any faster, but it does seem to have the effect of brake lights on the person following me.

What adjustments have you made?

Metro parking problem

Dear Dr. Gridlock:

A recent lunchtime meeting downtown had me considering taking Metro from Vienna to Metro Center. I try to be green and want to reduce traffic, but Metro's inefficiencies, poor performance and high cost make it hard to justify.

I arrived at the Vienna station about noon, and before the frustration of out-of-order escalators, rail cars without air conditioning and the $5.50 off-peak round-trip fare, I found all the garages full.

After searching both sides of Interstate 66 for a parking spot at the station (another 10 minutes wasted), I decided to drive into the District. Once at my destination near the Verizon Center, I immediately found an open meter within a block of where I needed to be, paid $3 for parking [compared with $4.50 for all-day parking in the Vienna garages or $1 per hour in metered spaces] and used about $4 in gas. Plus, I made it to and from my destination about 10 to 15 minutes faster than by Metro.

So just why should I consider Metro if it's more costly, more hassle, less comfortable and if I'm not sure I'll even find parking?

Clint Blocker


DG: You shouldn't. Midday parking at Metro lots and garages has become a big problem for many travelers. There's no way to predict whether a space will be available.

We're in a summertime lull right now, but September will mark the return of long-distance commuters who drive to the ends of the lines, park and board Metrorail.

Tips for working with what we've got: Remember that empty reserved spaces free up for all at 10 a.m. Mondays and Fridays and the lightest days for parking. Many people could avoid the parking hassle by taking a bus to the Metrorail station. Riders on most of our bus systems who have SmarTrip cards get a 50-cent discount when they transfer to Metrorail.

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