Why does Sacramento call speed bumps 'humps,' 'lumps' and 'undulations?'

by: Jeremiah Martinez

Posted: Jul 26, 2023 / 11:04 AM PDT

Updated: Jul 28, 2023 / 08:54 PM PDT

(KTXL) — When driving through the streets of Sacramento, it’s likely you’ve encountered a speed bump, even though it may be officially called by a different name.

According to an email from city of Sacramento spokesperson Gabby Miller, there are no “speed bumps” installed within city limits and those are only on private property.

Instead of “speed bumps,” Sacramentans might encounter “speed humps,” “speed lumps,” “undulations,” or “speed tables.”

These bumps or “raised devices” are designed to ease traffic in residential areas and near parks and schools.

The city of Sacramento implemented a Speed Hump Program in 1980 and has made several revisions to the program over the years.

The changes include street length criteria, a program change, the addition of a minimum speed requirement, and installing speed lumps for emergency responders and bus routes.

Undulations

According to the city, undulations are a pair of adjacent speed humps placed on the street and were installed on Sacramento streets prior to 1995.

There are 560 undulations in Sacramento and the city no longer installs new ones, Miller said.

Speed lumps

Speed lumps are similar in size to speed humps, being 12 feet wide and with a height between 3 ¼ and 3 ¾ inches.

The exception between a speed hump and a speed lump is the center of the speed lump has a width of 5 ½ feet to accommodate the wheelbase of fire trucks and buses.

According to the city, the lumps adjacent to the center lump depend on the width to accommodate how wide the street is. Depending on the street’s width, a 5 ½ foot lump may be placed in each travel lane.

After testing was done on these types of bumps in February 2000, speed lumps were installed after the approval of the Sacramento Fire Department for emergency response routes and by Sacramento Regional Transit for bus routes.

There are 1,247 speed lumps in Sacramento, Miller said.

Speed humps

Speed humps are single asphalt humps that are 12 feet wide with a height of 3 ¼ inch to 3 ¾ inches. They extend across the width of the road but are not installed on emergency response or bus routes.

There are 1,221 speed humps that were put on Sacramento streets between 1996 to 2006 and are no longer installed in the city, Miller said.

Speed tables

Speed or traffic tables are elongated speed humps covering a total of 22 feet of the street.

Tables incorporate a 10-foot flat surface in the middle of the road and have a height between 3 ¼ and 3 ¾ inches, according to the city.

These types of bumps were installed on Sacramento streets as part of the Neighborhood Traffic Management Program (NTMP).

According to the city, speed tables were added to the Speed Hump Program in 2008 on roadways with park or school frontage and posted speeds of 35 miles per hour.

Traffic tables were installed after the approval of the fire department and SacRT for use on a case-by-case basis.

There are no traffic tables within Sacramento city limits, as they have been changed to raised crosswalks or removed and replaced with speed lumps, Miller said.

If there are problems with cars speeding in a residential area, the city said a residential street could qualify for its Speed Hump Program if the following criteria are met:

•The two-lane street must be mainly residential or else have a park or school on the street•The residential street (or the part being considered) must be at least 750 feet long with no four-way intersections•There can be no other traffic control devices on the street segments such as four-way stop signs, traffic signals, etc. •The speed limit must be 30 miles per hour or less•Speeding of 5 miles per hour or higher over the speed limit occurs on the street•Street must be approved by Sacramento Regional Transit and the fire department

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