HomeMy WebLinkAbout2023-02-06; Traffic and Mobility Commission; ; Understanding Road Design its Effects on How People use the City’s Transportation SystemMeeting Date: Feb. 6, 2023
To: Traffic and Mobility Commission
Staff Contact: Tom Frank, Transportation Director/City Engineer
tom.frank@carlsbadca.gov, 442-339-2766
Subject:
District:
Understanding Road Design its Effects on How People use the City’s
Transportation System
Citywide
Recommended Action
Present an overview of how street design best practices have changed since Carlsbad’s road
system was first built.
Executive Summary
Since this is the first meeting for two new Traffic & Mobility Commissioners, staff will present
an overview of how street design best practices have changed since Carlsbad’s road system was
first built. At that time, the main focus was on wide roads that allowed cars to move quickly
through the city.
Updated laws, changing community values, and access to more data have combined to inform a
new approach called “complete streets.” This approach recognizes the street as a public space
that can be safe and inviting for all the ways people might want to get around, including biking,
walking and public transit.
This report provides information about the city’s complete streets policies, tools the city uses to
transform streets into complete streets and how the city prioritizes different modes of travel on
different streets.
Discussion
Traffic and mobility are always top of mind for the City of Carlsbad, and the city is committed to
helping everyone get around the city in a safe and convenient way, whether by foot, car, bike or
public transit.
Most of Carlsbad’s transportation system was built during the last 35 years, coinciding with the
city’s period of major growth. The policies that guided this development were focused mostly
on creating capacity on city roads so cars could travel without delays.
Feb. 6, 2023 Item #3 Page 1 of 6
Fast forward to today and for a variety of reasons this approach is changing to incorporate
complete streets. A complete streets vision is more than implementation of a state-mandated
approach during a general plan update process. It is a fundamental shift in how the city plans
and designs the street system – recognizing the street as a public space and ensuring that the
public space serves all types of people within the urban context of that system (e.g. accounting
for the adjacent land uses).
Carlsbad, along with many other state and federal governments, are finding ways to make
other modes of transportation a safe and inviting alternative where that makes sense.
In 2015, the City Council approved a new vision that recognizes that the city’s transportation
strategies in the future will be different. Instead of large new master planned communities,
Carlsbad will likely see what is known as “infill development.” Infill development refers to
building on unused and underutilized land, usually denser projects that also help meet housing
and environmental sustainability goals.
Designing for safety
No single solution will make our streets safer. Instead, it requires the three Es of traffic
safety: education, engineering and enforcement.
When it comes to engineering, the City of Carlsbad uses many different design solutions,
depending on a street's location, size and use.
Traffic calming
Traffic calming refers to changes to the road designed to improve safety by slowing down
cars. Street design is important because it’s a self-enforcing way to “calm” traffic and create
safe streets for everyone.
Think of it this way: People generally drive as fast as is comfortable given the roadway
conditions. That’s why people drive at higher speeds on wide, straight stretches but more
slowly when navigating down a narrow, winding road.
Visual cues, like a curve in the road, a narrow lane, a median, parked cars and other perceived
obstacles, cause drivers to naturally slow down and pay more attention to the road.
Transportation engineers call this friction.
Horizontal deflection prevents drivers from going in a straight line by creating a horizontal shift
in the roadway. This shift forces drivers to slow down to comfortably navigate the change in the
road.
Vertical deflection creates a change in the height of the roadway, which forces drivers to slow
down to maintain a comfortable ride.
Feb. 6, 2023 Item #3 Page 2 of 6
Roundabouts
Roundabouts are a safer alternative to traffic signals in most cases. Roundabouts lead to lower
speeds, have fewer opportunities for collisions and can typically carry about 30% more traffic
than similarly sized signalized intersections.
In Carlsbad: Carlsbad’s first roundabout along the coast is at the intersection of State Street and
Carlsbad Boulevard, at the city’s northern border.
Considerations: Some people have concerns that drivers and cyclists won’t know how to use a
roundabout, however, statistics show that they quickly adapt and are much safer.
• Roundabouts are designed so busses, trash trucks and emergency vehicles can easily
navigate them.
• Roundabouts often have landscaping or artwork in the center, which further works to
slow down traffic because it causes a vertical visual element that makes drivers to pay
more attention and yield to traffic coming from the left
• Collisions in roundabouts tend to be low speed and not result in serious injuries, unlike a
traditional traffic signal intersection, where t-bone and other serious collisions are
common.
Feb. 6, 2023 Item #3 Page 3 of 6
The effect of speeding
Reducing speeding, also called traffic calming, is an important consideration when designing or
redesigning streets. That’s because even small reductions in speeds can have significant effects
on the severity of collisions.
Feb. 6, 2023 Item #3 Page 4 of 6
How and when
The city has about 350 miles of local streets, meaning it will take many years to transform them
all. The city prioritizes street redesign projects based on a number of factors, such as safety
concerns, whether the street is located by a school or other sensitive use, and opportunistic
factors, like restriping a road that has recently been resurfaced.
The city’s policy is not to treat all streets the same. Instead, the General Plan Mobility Element
identifies different categories of streets and calls for design features based on the streets main
function. For example, a major street like El Camino Real may favor vehicle traffic while a
residential street may make more room for bikers and walkers.
The map below comes from the Mobility Element and shows how streets in Carlsbad are
categorized.
Finally, the recent local emergency proclamation on traffic safety in Carlsbad has elevated the
importance and visibility of the complete streets approach. Some residents have questioned
the changes, especially when it comes to making car lanes narrower. Others have concerns
about roundabouts.
The city recognizes the importance of raising awareness of the reasons behind these street
changes and why they improve safety. This is an area where the Traffic & Mobility Commission
can serve as a valuable forum for community outreach and education.
Feb. 6, 2023 Item #3 Page 5 of 6
Fiscal Analysis
This item is a presentation on the work related to management of the city’s transportation
assets and, as such, there is no financial impact related to this item.
Environmental Evaluation (CEQA)
Pursuant to Public Resources Code Section 21065, receiving a presentation on the work of the
Public Works Branch, Transportation Department does not constitute a “project” within the
meaning of the California Environmental Quality Act, or CEQA, in that it has no potential to
cause either a direct physical change in the environment, or a reasonably foreseeable indirect
physical change in the environment.
Public Notification
This item was noticed in accordance with the Ralph M. Brown Act and was available for public
viewing and review at least 72 hours prior to the scheduled meeting date.
Feb. 6, 2023 Item #3 Page 6 of 6
Road Design
Then & Now
Tom Frank
Transportation Director/City Engineer
Feb. 6, 2023
UNDERSTANDING ROAD
DESIGN
•“Complete streets”
•Carlsbad laws and policies
•Examples
•What’s next
3
Designed for cars
1980s
Wide lanes = high speeds
No bike lanes
No place to walk
4
Today
Accessible for all
High-visibility crosswalks
Sidewalks
Lighting, greenspace,
benches
Transit Buffered bike lanes
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7
8
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10
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Why?
•Complete Streets law
•General Plan Mobility Element
•Sustainable Mobility Plan
•Safer Streets Together Plan
Foundational Elements
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What’s more inviting?
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The importance of speed
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DESIGN FEATURES
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DESIGN FEATURES
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DESIGN FEATURES
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DESIGN FEATURES
Horizontal Design
ITEM 4: COMPLETE STREETS WORKSHOP
1. What’s the current and future demand?
2. Address capacity
3. Balance mode area and lane widths
37
Horizontal Design
ITEM 4: COMPLETE STREETS WORKSHOP
Bicycle Design
ITEM 4: COMPLETE STREETS WORKSHOP
•Pedestrian Crossings
•Intersection Control
•Traffic Calming
•Others
39
Potential Future Topics
ITEM 4: COMPLETE STREETS WORKSHOP
Bikeway Design
Questions?
ITEM 4: COMPLETE STREETS WORKSHOP