Portland is a PR machine for light rail & streetcar
Here are Some Facts About Portland Oregon
One-Way Streets safer then Two-Way Streets
ONE-WAY STREET SYSTEMS
Studies were conducted from the 1930's to the 1970's of "before" and "after" conditions
as cities switched from two-way to one-way streets. Almost universally they found
that one-way streets had 10-20% lower accident rates than when previously two-way.
Most significantly, pedestrian accidents plummeted by 30-60% (Pages A-126; A-162,
Source 1; Pages 7-2 to 7-8, Source 2; Source 3; Page 28, Source 4; and Chapter 10,
Source 5). As one traffic safety expert noted: "Conversion from two-way to one-way
street systems has consistently been found to reduce pedestrian accidents" (Source
Nothing the City of Portland has done to reduce pedestrian accidents in the past
70 years has been as effective as implementing one-way streets. When the City of
Portland converted most of its downtown street system to one-way in the late 1940's
it found a 50% decline in pedestrian accidents, a decline in auto accidents, higher
speeds, better traffic flow, and what seemed like emptier streets (because of the
wider gaps in traffic), These results were typical of the many cities that made such
conversions. All forms of transportation benefited: pedestrians the most, but also
buses, autos, trucks, and bicycles. It has proven to be a win-win proposition where
Since 1980 several one-way streets have been converted back to two-way flow in downtown
areas. In 1986 Denver converted seven streets on three one-way couplets. Average
intersection accident rates increased 37.6% while average mid-block accident rates
increased 80.5%. The City report noted that accident rates were up on all three
couplets "as is expected with two-way operation" (Pages 23 and 29, Source 7). Lubbock,
Texas in 1995 converted two streets back to two-way. Overall accident rates increased
there 41.6% (Source 8).
One-way operation permits much better traffic signal progression for smoother traffic
flow. This results in traffic moving at regulated speeds with less stop-and-go driving.
Less fuel is consumed and there is less air pollution. One-way signalized operation
also tends to cluster traffic into "platoons" with wide gaps between them . This
makes it much safer and faster for cross street traffic, bicycles, and pedestrians
to cross major streets.
Another benefit is in use of space. Because one-way streets move more traffic per
lane than two-way streets cities with one-way systems need to devote less space to
roadways. Four lanes of a one-way couplet carry as much traffic as a seven-lane two-way
street. The one-way dynamics leading to superior safety and capacity are similar
to why three-way intersections work better than four-way ones. A grid with only one-way
streets has only two-way intersections.
FHWA - Federal Highway Administration (USDOT)
1) "National Highway Safety Needs Study, Appendix A", Research Triangle Institute,
March 1976 (DOT-HS-5-01069).
2) "One-Way Streets and Reversible Lanes", Synthesis of Safety Research Related to
Traffic Control and Roadway Elements, Volume I, Research Triangle Institute, March
1976 (FHWA-TS-82-232), December 1982.
5) Peter A. Mayer, Chapter 10, "One-Way Streets", Traffic Control and Roadway Elements,
Their Relationship to Highway Safety, Highway Users Federation for Safety and Mobility,
6) Dr. Charles Zegeer, University of North Carolina, "Engineering and Physical Measures
to Improve Pedestrian Safety", from 1988 WALK ALERT Program Guide, National Pedestrian
7) City of Denver, "One-Way Street Monitoring Study, Phase 1 Conversion Report",
January 1990. (The seven streets were Grant, Logan, Washington, Emerson, Downing,
Marion, & Ogden Streets. Data on accident rates is from pages 15, 23, and 29).
8) City of Lubbock, "Main and 10th Street Accident Analysis, Before/After Study",
The attached two Excel tables are extracted from the data shown in the most comprehensive
study I have found on two-way to one-way conversions and provide a snapshot summary
of the safety impact of converting major two-way streets to one-way flow. The study
was the Oregon State Highway Department, A Study of One-Way Routings on Urban Highways
in Oregon, Technical Report #b 59-4, April 1959, Salem, Oregon. This study examined
“before” and “after” accidents and traffic volumes in twelve cities in Oregon from
the 1930’s to the 1950’s. Because of the large sample size, variety of communities,
and differing circumstances of each one-way couplet implemented during this period,
this landmark Oregon study provides very comprehensive data on the safety impact
of one-way streets and is the most definitive study I could find on this subject.
The tables provide not only the impact for each individual one-way couplet but a
weighted average summary of the composite impact of all of them on the state highway
system. The results are definitive and quite similar to those obtained in many large
city studies of two-way to one-way conversions on city streets during this same period
and later. While speeds and flow rates generally increased, overall accident rates
declined by over 24%. Injury accidents declined by 26.1%. This debunks the theory
that higher speeds inevitably lead to higher accident rates. The opposite is the
case in one-way conversions because traffic flow is simpler, has fewer turning conflicts,
and allows a higher degree of motorist concentration on fewer issues. Even more impressive
is the impact on pedestrian accidents. The pedestrian accident rate declined 37.6%,
considerably more than the vehicular accident rate. This same result is also evident
in the major city studies. Pedestrians benefit the most from one-way street systems.
Again, this debunks prevailing “traffic calming” claims that converting one-way streets
back to two-way would makes them “more pedestrian-friendly”, the over-worked cliché
phrase used throughout North America. This is rue only if one’s idea of friendliness
is to have more pedestrians hit by vehicles.
A detailed study of the intersections showed that " pedestrian accident ratios "
and "crosswalk use ratios " tend to cover a range of values . But, in general, the
study showed that in terms of usage " approximately twice as many pedestrian accidents
occur in marked crosswalks as in unmarked crosswalks.
Of particular importance were the findings, based on 5 years of accident experience
at 400 unsignalized intersections, that pedestrians in the 25-44+ year age group
had no accidents in unmarked crosswalks, but were involved in 25 accidents in marked
crosswalks . The 65-69 year age group showed a similar pattern with no accidents
in unmarked crosswalks, but 13 accidents in marked crosswalks . Also of concern was
the fact that during this 5 year period 49 pedestrian accidents occurred in marked
crosswalks during the 5-7 p .m. time interval but during this time no accidents occurred
in unmarked crosswalks.
This, plus other evidence, suggests that the poor accident record of marked crosswalks
is not due to the crosswalk being " marked " as much as it is a reflection on the
pedestrian's attitude and lack caution when using the marked crosswalk . For this
reason marked crosswalks should not be installed unless they are truly warranted.
City of San Diego, California, Police Department, Traffic Bureau, Public Works Department,
Traffic Engineering Section
Sacramento: One Way Streets OK for business!
In Portland, Oregon*, which on March 1, 1950 established a complete grid of one--way
streets in the central west side business area, accidents were greatly reduced .
In 1951, compared with 1 .949, all types of accidents at intersections were reduced
51 per cent and, between intersections, 37 per cent . The corresponding figures for
pedestrian accidents alone, were 46 and 50 per cent.
On several occasions, semi-trucks were observed abruptly stopping to yield to pedestrians.
While these drivers were obeying traffic laws, this situation increased the risk
of a “multiplethreat” collision when the truck yielded in the near lane. Even when
these trucks did yield at the advance stop bar, the size of the trucks blocked the
sight distance for both the pedestrian and any motorists in the far lane. Some pedestrians
were observed stopping mid-crossing and “peeking” around the truck to see if the
far lane was clear. One near “multiple-threat” crash was observed when a school bus
yielded in the near lane and a vehicle in the far lane nearly collided with the crossing
Final Report, SPR 304-321, July 2005, Oregon Department of Transportation, Research
Unit and Federal Highway Administration
In summary, conversion from two-way to one-way street systems has consistently been
found to reduce pedestrian accidents,
because it can greatly reduce the complexity of crossings for pedestrians and allows
motorists to pay more attention to crossing
pedestrians . Where one-way street systems are feasible in terms of traffic-circulation
patterns, improved pedestrian safety
is a likely result.
Conditions Where One-Way Streets Are Most Beneficial
Downtown grid street networks, particularly on narrow streets with high traffic volumes.
Streets with inadequate gaps for vehicle turns.
Streets with heavy pedestrian activity and a high frequency of conflicts between
turning vehicles and pedestrians.
Where there is a substantial number of left-turn accidents, right-turn accidents,
and/or midblock pedestrian accidents.
Conditions Where Least Beneficial or Possibly Harmful
When vehicle speeds would be substantially increased as a result (e .g ., some very
wide streets) .
From PEDESTRIANS AND TRAFFIC-CONTROL, CHARLES V. ZEGEER,Highway Safety Research Center,
University of North Carolina, TRANSPORTATION RESEARCH BOARD, NATIONAL RESEARCH COUNCIL,
WASHINGTON, D .C ., NOVEMBER 1988, page 28
Sacramento found a 62 percent reduction in pedestrian accidents