Wednesday, October 22, 2008

Council tangles with speed limit conundrum


In a move they openly termed counterintuitive, Santa Barbara city leaders agreed yesterday on a 5-2 vote to lower speed limits on Haley Street and increase speed limits on De la Vina Street.
Their reason for making the seemingly backward decision is intricately linked to the method currently used to set speed limits and their desire to give police officers the tools to crack down on speeders.

As explained by the city’s transportation engineer supervisor, Dru Van Hengel, speed limits on many city streets are based on speed surveys taken approximately every five years.
Traffic engineers are bound by law to set a baseline for speed limits by judging the 85th percentile of speeds being traveled on a given street — that is, essentially cutting off 15 percent of the fastest drivers and using the next highest speed.
The city must set the speed limit at the closest 5-mile-per-hour increment. Engineers can then lower that limit by 5 mph for a variety of reasons, such as bicycle and pedestrian safety, visibility concerns and collision rates.
So when the city’s traffic engineers studied a group of local streets to update their speed surveys, drivers on De la Vina Street delivered a baseline of 35 mph, while those on Haley Street set it at 30 mph.
Van Hengel explained that engineers took into consideration pedestrian and bicycle safety, as well as collision rates and visibility issues, and lowered both recommended speed limits to 30 and 25 mph respectively. The move effectively swapped the current speed limits on each street.
“You’re reducing it on the wide street and increasing it on the narrow, constrained street,” Councilmember Iya Falcone said.
It might seem obvious, then, to toss the new survey and keep the original speed limits. But doing so would strip police officers of their ability to enforce those speed limits.
“When the speed survey expires, we can no longer use radar on that street,” said Sgt. Todd Stoney, traffic investigation supervisor with the Santa Barbara Police Department.
When officers go to court to testify on speeding tickets, the first thing judges ask for is the engineering survey, he said. The only other way to catch speeders is to follow them in a squad car at the same speed for a certain distance, a method Sgt. Stoney described as unsafe.
“Essentially, we can no longer work those streets,” he said.
So by raising the speed limit on De la Vina Street between Micheltorena and Haley streets, the city will actually permit police to go after speeders. And by lowering the limit on Haley Street between Chapala and Milpas streets, they’ll accomplish the same goal.
“We’re being forced to increase the De la Vina area by 5 mph because we have to start with a higher baseline,” Councilmember Helene Schneider said. “…We can’t wriggle around that.”
That is, Van Hengel said, unless the city decides to reclassify its streets.
Many of Santa Barbara’s streets are officially classified as “arterial” or “collector” streets under federal standards, meaning they are eligible for federal funds for construction, rehabilitation, resurfacing and operational improvements.
“Yet many of our streets, although designated as arterials, don’t really display the typical look and feel of an arterial,” Van Hengel said.
Arterial and collector streets are largely dedicated to thru traffic, with few driveways and little on-street parking, she explained. On the other hand, streets classified as “local” have plenty of driveways and parking.
More importantly, Van Hengel said, radar-enforceable speed limits can be set on “local” streets without a speed survey.
She explained that the city classified many of its streets as arterials or collectors years ago in order to garner federal funds. By reclassifying them as local, city leaders could come up with their own speed limits, but would lose out on the funding.
While that amount is not known, Van Hengel said Caltrans officials described it as negligible when compared to the overall federal and state funds available for street improvements.
The council seemed in favor of studying that option in more detail, giving staff the go-ahead to launch a yearlong effort to that effect.
Councilmember Dale Francisco expressed a bit of hesitancy, citing concerns about the financial downside. And while reclassifying De la Vina Street, for instance, makes sense, Francisco said some arterial and collector streets should not be “artificially” reclassified.
His reason for voting against the item stemmed from changes to the speed limit along Haley Street. He called the need to change the limit along De la Vina Street unfortunate but understandable under the circumstances, but said he couldn’t understand the need to drop speeds on Haley Street to 25 mph.
“It seems to be functioning well from what I can see,” he said. “…It seems unreasonable to reduce by 5 mph the speed when it seems to be working fine.”
Van Hengel cited pedestrian and bicycle safety concerns, along with a higher collision rate and limited sightlines from side streets, as the underlying reasons for dropping the speed limit. She said the collision rate for the area is 2.64 accidents per million vehicle miles traveled, compared to a Caltrans standard of 1.77.
Councilmember Roger Horton, who also voted against the proposal, said he simply did not have enough information on how the changes will impact the police department.
Ultimately, a majority of the council decided to set the new speed limits and conduct a speed survey along those streets in three years instead of five to determine if they need another update.
Public Works Director Christine Andersen, while empathizing with those who live along De la Vina Street and deal with speeders, said the city had its hands tied when it came to getting an enforceable speed limit on the books.
“We’ve got speeding going on along De la Vina … and the police can do nothing about it,” she said. “This will allow police to go out there and enforce at the 30 mph speed limit.”


benburleson said...

They better enforce it then!

Anonymous said...

Patience? This concept is something that our younger drivers, 18-30 years old, missed when being educated by their parents. Just come to my neighborhood on the Mesa, and watch the impatient drivers exceed the 25mph by 10-30mph just to get to the next controlled(?) intersection. Just because of the impatience of some/most drivers we reward that behavior? Something is wrong here!

allegro805 said...

This was a really well written and comprehensive article about the process, and I understand a lot more about how speed limits are set than I ever did. Thank you.

Let's hope the PD actually gets out and cracks down on excessive speeding on De La Vina now, and I hope the Council really considers changing the classification of some streets to "local" after a yearlong "study."

Anonymous said...

I thought that the traffic lights on De la Vina were synchronized for smooth traffic flow. Will this upset the synch?

Jeanine Conway said...

I think there was a confusion on what the actual conundrum was, during this meeting. Speed limts are set by state and federal standards, which gives agencies methodology in which to go by, and protects citizens from being unreasonably ticketed if the speed is set at an arbitrary number. The Council was just super confused about their own role.What wasn’t said is that speed limits are always set like this and its only in cases where a speed limit changes and the street is listed in the Schedules section of Mucipal Code section 10.60 that the council must make a decision.

The City council is given this authority to allow speeds to be set greater than 25mph if on the basis of traffic speed methodology in determining the speed. This actually brings up a question (outside what I personally believe about Haley Street) If you look at the code in section 10.20.15:

Pursuant to Section 22357 and 22358 of the Vehicle Code, the City Council hereby determines, upon the basis of engineering and traffic investigation, that a speed greater than 25 miles per hour would be reasonable and safe upon the streets designated in Section 10.60.015 of this Code

It seems that the Council has no say if the speed is going to be 25mph, only when it is raised above 25mph. It should only be a procedural exercise in rewriting the Code for Haley Street, not a discussion. ( it’s the burden of the traffic staff to prove that the street is reasonable and safe get it back on the list at higher than 25 in the future) I am not a lawyer so I don’t know if this is true.

The reason speed zoning issue ever came up was a very slight change in the method of determining posted speed. A guideline in the MUTCD (the manual in which state and local agencies base the speed zone surveys) has been rewritten in the last year which determines what speed shall be posted based on the 85% speed surveyed. Previously, the speed could be set “within 5mph of the 85%”; now the change was made that speeds shall be set “to the nearest 5mph”. (25,30,35,40 etc) forcing to round up in some cases.

85% is the speed in which 85 percent of drivers drive at or below. (the basis of what percieved safe speed a typical driver will drive)

Example of the impact.

Previously, if the 85% speed was 33 or 34mph, the speed posted could be set at 30mph.
Currently, if the 85% speed is 33mph, the speed posted shall be posted to 35mph (rounded up)

The reality is that now when a new survey is conducted for a street in the city, the posted speed may change, even if the actual speed drivers travel doesn't. When surveys expire a new one is created if there is a continued need for enforcement. This recent discovery is what put a conundrum on the options available. The extra 5mph reduction is a tool in which engineers can use, when the desired posted speed is not achieved. (Previous practice almost always resulted in posting the speed limit on the lower 5mph increment, or rounding down) This is also the reason that the police will only enforce speeds starting at 10mph over the posted speed. In order to uphold in court a speeder needs to be proven to be traveling over 7 to 8 miles over the prevailing speed or 85%. Police don’t know at face value what that is without memorizing the surveys, so they play it safe. On De La Vina, cars would have to travel over 40 to get a ticket now. There is extreme pressure on City and the Police to address percieved dangerous areas of the City.

My personal opinion is that Haley should stay the same, but if its get reclassified in the business district, than so be it. De la Vina should be signed correctly, but should be restripped to one lane and bike lane (like Bath) south of Carrillo after the next slurry seal resurfacing, and whether or not 30 would stick, one problem would be addressed; lowering the high collision rate.

Let's push to restripe De La Vina!

Sharron said...

As a resident on De La Vina, this change of the current speed limit to a higher one makes no logical sense except when viewed from the questionable fiscal viewpoint of the city obtaining federal funds. Our street is two lanes of one-way traffic with parking on either side and often used as a racetrack by speeding vehicles. Accidents are a common occurence. Bicyclists choose to ride illegally on the sidewalks because the street is too dangerous for them. Pedestrians are of low priority. Surely quality of life for the De La Vina St. residences should be a primary concern rather than federal funds. A change to one lane only with a bike lane ought to accompany a higher speed limit.

Jessie said...

I work a block off Haley and can testify to how excessively fast the traffic is- fine I guess, if you are trying to get from State St to Milpas ASAP, but really dangerous for those of us who live or work in this neighborhood and walk or bike this route. I will readily admit to illegally riding my bike on the sidewalk so that I don't have to risk my life on the street. Additionally, I sure hope that they CLEARLY post the new speed limit, as the existing signs are few and far between. I really had to look hard to figure out that the existing limit is 30 mph. And please, please enforce it! Keep us safe.

BRC said...

I don't understand: I thought they could catch speeders with radar guns, not just by following them a certain distance?

Haley Street is very dangerous for bicylists and lowering the speed limit to 25 MPH won't help. There are no reasonably safe bicycle routes to get from the lower east side to downtown, short of zig-zagging on different streets and of course using the sidewalks. ...I am not suggesting that Haley be narrowed to two lanes as is being suggested for de la Vina!

Dela Vina Street has the adjacent bicycle lane on Bath; doesn't need another, imo. It certainly doesn't need to have its speed limit raised - it's already a racetrack. Instead of going 35, people will now zoom at 40.

There's something wrong here!

David Pritchett said...

As the article indicates rather well for a reporter who was not even in the Council meeting room, the police cannot do speed enforcement with radar unless the formal Engineering Traffic (speed) survey is current. Thus, the conundrum (as I said to the City Council) results that in order for the police to enforce the speed limit the limit therefore has to be raised in compliance with the speed survey so radar can be an enforcement tool.

How much speed enforcement the police really will do now has become the dependent variable for whether speeds really will slow down on De la Vina St. downtown.

The data from the recent speed survey show that the 85th percentile speed already is close to 35 mph in the current zone posted at 25 mph, meaning that without this action to raise the speed limit to 30 mph then the vast majority of speeds still would be close to 35 mph UNLESS the police are doing more enforcement as an incentive for driving at the new speed limit of 30 mph.

Yep, this is quite a counter-intuitive conundrum. Besides overall not having enough police for speed enforcement, the root of the conundrum is an arcane State law that prohibits radar enforcement without a current speed survey.

The long-term solution, which the City Council approved, is to reclassify most of the residential streets as "local" streets with an automatic speed limit set at 25 mph, including De la Vina St. downtown. With that new classification enacted, then speed enforcement with police radar will become legal again, and to enforce at a speed limit of 25 mph in the truly residential streets, such as De la Vina Street is.

Until the City Council action yesterday, the police COULD NOT enforce with radar because the speed survey had expired. The new updated speed survey revealed that so many drivers were zipping at close to 35 mph that the speed limit had to be raised to allow legal enforcement with radar. The new limit is 30 mph because a plus or minus 5 mph deviation is allowed under the current law.

The Federal funds so far have not been a factor in the deciding, especially because no one yet has confirmed the amount of those funds anyway. So far, the best estimate are that the funds no longer available to the City would be "negligible" if the streets are reclassified as local status where supposedly Federal funds no longer would be appropriate for a locals-only street use.

Again, the new classification of all residential-like streets, to 25 mph possibly, is the mechanism that will allow the City police to enforce with radar. Two of us on the City Transportation Committee (appointed by City Council) will assist the City staff to Keep It Real on how the street classification is conducted objectively and expeditiously to follow the procedure specified by CalTrans so the streets can be reclassified to Local status instead of Collector or Arterial status.

I will write a lot more about this in a future posting at Edhat and in a video production of "Off-Leash Public Affairs" early next year. My video will not be the sanitized version of the story we all no doubt soon will be able to see in a City-produced episode of their video show "Inside Santa Barbara".

john Rettie said...

There is a very good chance that the average speed of traffic on De La Vina will decrease with a higher, but more realistic, speed limit. It happens quite often as drivers are more likely to drive at the posted limit when it is reasonable.

As an example, there is a major street in Santa Barbara with a posted speed limit of 55mph and yet it is rare for anyone to go over as it is an entirely reasonable speed.

It has been proven in the UK that artificially low speed limits can be more dangerous than higher ones as pedestrians and bicyclists have a false sense of safety..

allegro805 said...

I think you're probably twisting things to suit yourself, john rettie. Who defines "reasonable" speed? The rushing soccermom in a Hummer? The dead pedestrian?

Also, why won't you name the "major" street on which it's "rare" for anyone to go over the 55mph posted limit?

Please cite your UK sources.
What I don't understand about this whole thing is how limits get set by studying the current average speed. Doesn't that sound a**-backwards? So if the average speed of all drivers on De La Vina were 45 or 50 that would mean by law the limit would have to be raised?

Anonymous said...

Good article and discussion.

Raising the speed limit on De La Vina so that cops can write tickets is a dumb idea. They could write all the tickets they want by busting the people who don't yield to pedestrians trying to cross the street.

SteveJ said...

Traffic on De La Vina is fastest between Carrillo and Haley, a 5-block stretch with no stop signs or lights. I was told at a recent City-sponsored neighborhood meeting that there were plans for a "traffic calming" (e.g. narrowing at an intersection) enhancement for that stretch of De La Vina. A simpler but potentially effective action would be painted pedestrian crossings; those seem to be working at Garden and Sola.

Anonymous said...


The world is round not flat. That may sound a**backwards to you but it's a FACT. California state law requires a speed study for radar speed enforcement.

Claims of unsafe speeds and high accidents on De La Vina should be supported by a history of the accident data. So where is the accident data? Good luck finding it because it doesn't exist.

allegro805 said...

Dear Anonymous (nice name): Thanks for being so condescending. I'm sorry that my straightforward question reeked to you of being a Flat-Earther.

I understand that streets classified a certain way legally require speed studies. My question was whether "the average speed actually being driven" is a good indicator of what the legal speed limit should be set at. THAT is what seems a**backwards, because basically you are letting "the average driver" in effect "set" the speed limit. Is that correct?

Does that mean the assumption is that "drivers, in the long run and on average, will only drive at speeds that are safe for any given street"? (sort of like "all economic markets and prices set their own equilibrium in the long run"??).

I'm sure there actually is accident data for the DLV corridor, and that was presented to the Council. Is your assertion that there are NO accidents on DLV? Who's buying into flat-earth scenarios now?

Note also that radar enforcement IS allowable WITHOUT a speed study if a street is classified as "local". Did you read the article?

I was merely asking a question about methodology and the assumptions behind it. However, if you are asserting that no "excessive" speeding is going on on the DLV/Chapala corridors, I think you are out of touch with reality.

Anonymous said...


It's not average speed, it's 85th percentile. Roadway accidents are not always related to speed or speed limit. There could be 50 accidents on a roadway and all could related to drunk drivers. The speed study showed that 35 mph is the 85th percentile speed, which is far from being excessive. So yes you are a flat earther, if you think speeds are excessive on De La Vina..