State Route 246

1
State Route 246 Purisima Road Safety
Improvement Project Paul Valadao,
Caltrans District 5 April 22, 2009
Lompoc City Hall
2
Purisima Project Purpose, Need, and Status
State Route 246 Purisima Road Safety
Improvement Project

• Need Collision rate at intersection of Purisima
  Road and Hwy 246 is four times state average
• Purpose Project will eliminate potential of
  broadside collisions, and severity of collisions
  will decrease with lower speeds
• Project is in the Environmental Phase

3
State Route 246 Purisima Road Safety
Improvement Project
4
State Route 246 Purisima Road Safety
Improvement Project
Aerial view of Highway 246 and Purisima Road with
Proposed Roundabout Design
5
Why a Roundabout and nota Signalized Intersection
State Route 246 Purisima Road Safety
Improvement Project

• Increase Safety
• Increase Capacity / Reduce Delay
• Accommodates Larger Vehicles
• Less Maintenance
• Reduce Vehicle Emissions

6
Roundabouts vs. Signalized Intersection
State Route 246 Purisima Road Safety
Improvement Project

• Safety Reduces Points of Conflict from 13 to 4
  and Eliminates Crossing Conflicts Entirely

7
Roundabouts vs. Signalized Intersection
State Route 246 Purisima Road Safety
Improvement Project

• In the 2008 Federal Highway Administration
• (FHWA) Study involving both transportation
• professionals and volunteers from the general
  public
• Roundabouts were chosen as one of nine proven
  safety countermeasures.
• Of the nine, roundabouts were the only
  intersection safety countermeasure listed.

8
Reduce Number Severity of Collisions
State Route 246 Purisima Road Safety
Improvement Project

• In the 2007 National Cooperative Highway Research
  Program
• Report 572, 55 intersections throughout the U.S.
  were
• converted from a signalized or stop controlled
  intersection to a
• roundabout. Two years of collision data showed
  the following
• Number of collisions were reduced by 35
• Number of injury collisions were reduced by 76
• When compared to a suburban signalized
  intersection, the number of collisions were
  reduced by 67
• When compared to a rural two-way stop controlled
  intersection, the number of collisions were
  reduced by 87

9
Reduce Vehicle Delay
State Route 246 Purisima Road Safety
Improvement Project

• In the 2004 Kansas Department of Transportation
• Study, 11 intersections were converted from a
• signalized or stop controlled intersection to a
• roundabout
• Average vehicle delay was reduced by 65
• Average vehicle stops were reduced by 52

10
Accommodates Larger Vehicles
State Route 246 Purisima Road Safety
Improvement Project

• The geometry of a roundabout includes a truck
  apron that accommodates vehicles with large
  turning radii, such as buses,
• trucks, tractor trailers,
• farm equipment, and
• emergency vehicles.

11
Accommodates Larger Vehicles
State Route 246 Purisima Road Safety
Improvement Project

• The proposed design will accommodate vehicles
• from the local area, farms, businesses and
• Vandenberg Air Force Base

12
Maintenance
State Route 246 Purisima Road Safety
Improvement Project

• Signals require continuous routine surveillance
  and inspection.
• Signals require a human response when a suspected
  malfunction is reported.
• When considering the landscape maintenance cost
  associated with a roundabout, the comparative
  lifetime maintenance cost for a signal is higher.

13
Reduce Vehicle Emissions
State Route 246 Purisima Road Safety
Improvement Project

• In the 2004 Study of Roundabouts Across the U.S.,
  
• roundabouts were shown to
• Reduce Carbon Monoxide Emissions by 32
• Reduce Nitrous Oxide Emissions by 34
• Reduce Carbon Dioxide Emissions by 37
• Reduce Hydrocarbon Emissions by 42
• In the 2002 Study of Roundabouts Across the U.S.,
• roundabouts were shown to
• Reduce Fuel Consumption by 30
• Mandavilli, S. Russell, E.R. and Rys, M. 2004.
  Modern roundabouts in United States an efficient
  intersection alternative for reducing vehicular
  emissions.
• Poster presentation at the 83rd Annual Meeting of
  the Transportation Research Board, Washington,
  DC.
• Várhelyi rhelyi, A. 2002. The effects of small
  roundabouts on emissions and fuel consumption a
  case study. Transportation Research Part D
• Transport and Environment 765-71.

14
Project Schedule and Cost
State Route 246 Purisima Road Safety
Improvement Project

• The schedule for this project is
• Currently preparing Environmental Studies
• Project Approval and Final Environmental Document
  (PAED) August 2009
• Ready to List (Project Out for Bid) April 2011
• Construction Complete Spring 2013
• The estimated capital cost for construction,
• right of way acquisition, and utility relocation
  is
• 3.5 million.

15
Comments and Questions
State Route 246 Purisima Road Safety
Improvement Project

• Ask the staff present at the Open House
• Submit comments via comment card at the Open
  House
• Submit comments by May 7, 2009 to Chief of the
  Environmental Planning Branch
• Matt Fowler, Senior Environmental Planner
• Department of Transportation
• 50 Higuera St
• San Luis Obispo, CA 93401
• or [phone]
• or matt_fowler_at_dot.ca.gov

16
State Route 246 Purisima Road Safety
Improvement Project
For More Information
Project information posted on Caltrans District 5
website http//www.dot.ca.gov/dist05/projects/ o
r contact Sara von Schwind Project Manager at
[phone] or sara_von_schwind_at_dot.ca.gov