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Evidence
on performance
Bologna Car-Restricted Zone: Zona a Traffico
Limitato, Italy
Barcelona Access Control: Poble Sec and La Ribera, Spain
Sao Paulo Number Plate Restriction: Rodizio, Brazil
Athens Odd and Even Number Plate system, Greece (forthcoming)
Bologna Car-Restricted Zone: Zona a Traffico Limitato,
Italy
Display location
Topp and Pharoah (1994) report the impacts of a car-restricted zone in
Bologna. Cairns et al (1998) provide the evidence of Bologna as a case
study. TRANSLAND (1999), the EU research project in the field of integrated
transport and land-use planning, also covers Bologna as a case study for
good planning practice.
Context
Bologna is a large historic centre with narrow and irregular streets and
has the old town encircled by a large four-lane ring road. First attempts
at traffic limitations began in 1972, including the introduction of a
pedestrian area and bus lanes, and restrictions on private vehicle movements.
In 1984, a new comprehensive plan was introduced by a referendum, in which
75% of Bologna residents voted in favor of the selective restriction of
the city centre for private automobile traffic. This plan included access
control to the old town, parking management and extension of the pedestrian
area.
In 1989, the car-restricted zone "Zona a Traffico Limitato",
which contains the entire old town, was introduced as a permanent regulation.
Access by motor vehicle was restricted between 7 a.m. and 8 p.m., except
for the following certain categories of vehicle having access permits*:
- buses of the public transit operations;
- taxis and emergency service vehicles;
- residents cars (about 25,000);
- vehicles of trade business and shop owners located in the city;
- delivery vehicles (only at set times) (about 15,000);
- hotel guests from outside the Bologna region;
- holders of private parking spaces.
(*List based on TRANSLAND (1999) and complemented from Topp and Pharoah
(1994))
The access control was supplemented by other measures including parking
restriction. There is only one large public car park for long stay and
residents are allowed to park only in their own quarter. However, thousands
of park-and-ride spaces were built outside the ring road, together with
additional free parking for transit pass holders or bicycle owners. Other
implemented measures are as following:
- extension of the short term parking zones on the edge of the historical
centre;
- introduction of a 30 kilometre per hour speed limit in the entire
restricted area;
- re-organization of the municipal bus transit services;
- strict surveillance of access through parking control;
- extension of the pedestrian zone at the expense of an arterial road.
(TRANSLAND, 1999)
The twelve entry gates into the historical centre were only marked with
signs showing restricted access to alert drivers. In 1994, the first five
access gates installed a telematic system. The presence of non-stop access
control is that an additional signal confirms validation to those vehicles
equipped with an On-Board Unit, but not to vehicles validated via the
Optical Character Recognition (OCR). This telematic system provides flexibility
for handling non-equipped vehicles. For example, a car driver staying
at a hotel inside the controlled zone registers the vehicle number plate
when checking in, and this is then relayed to the control centre to suppress
the issue of a fine.
Impacts on demand
The local government provided the data: the total number of vehicles (cars
excluding taxis) entering and leaving daily the old town was reduced from
177,000 (152,000) in 1981 to 87,000 (58,000) in 1989. The reduction of
all vehicles was 49% and private cars dropped by 62%. This was achieved
without major traffic increases on the ring road, though through traffic
was reassigned to the ring road. However, car limitation has been recently
eroded because the large number of permits and weak enforcement led to
increases in traffic (Topp and Pharoah, 1994).
Bus transport achieved shorter journey times and provided more punctual
service because of less traffic on the bus routes in the old town. Bicycle,
taxi and motorcycle traffic has grown. In 1990, the modal split for those
visiting the old town was approximately 78% bus, 11% private cars and
8% bicycle or motorcycle. The modal split for trips within Bologna is
31% walking, 2% bicycle, 33% public transport and 34% private cars.
The restrictions end at 8 pm, after in which evening "leisure time
traffic" pours out onto the streets and forms long car lines through
the old town and ruins evening walks (TRANSLAND, 1999).
Impacts on supply
The supply of road space has not changed as a result of the car-restricted
zone. However, more recently, the local government has undertaken a series
of actions:
- development and upgrading of fringe park and ride nodes;
- development of new parking lots in the intermediate periphery and
operation of shuttle lines for old town connections;
- promotion of public transit use by: i) enlarging and updating the
vehicle fleet (including electric vehicles), ii) redesigning the public
transit circulation, iii) modernizing the bus shelters, iv) implementing
the tele-monitoring system for prompt user information on schedules
and traffic situation, v) improving user information on prices, services
and intermodal opportunities;
- development of new bicycle infrastructure (parking and reserved lanes).
(TRANSLAND, 1999)
Contribution to objectives
Bologna encompasses the historical city centre, which not altered since
the 13 century and was built for pedestrian traffic. This may raise the
quality of life and livelihood of the city centre for both residents and
visitors. Contribution to objectives below is completed on the basis of
contribution to overall access control policy objectives.
Contribution to objectives
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No analysis has been conducted, but the reduction of congestion
will have increased efficiency.
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No analysis has been conducted, but the reduction of congestion
will have improved liveability.
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No estimation has been made, but the reduction of congestion will
have reduced air and noise pollution and saved the historical buildings,
ancient monuments and ruins.
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Improvements in bus transport, bicycle and motorcycle services
have made the transport environment more equitable and reduced the
potential for social exclusion through lack of access to a car.
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The reduction of congestion with no significant increase in speeds
will have improved safety for pedestrians, cyclists and cars travelling
next to each other. Average speeds in the old town can rarely exceed
15 km/h, with the 30 kilometre per hour speed limit as a supplementary
measure (TRANSLAND, 1999).
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No analysis has been conducted, but the reduction of congestion
will have reduced associated costs to the economy.
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Automatic vehicle identification (AVI) technology was used at
several entry gates, but with little financial investment.
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In the 1984 referendum, most public supported the measure. This
measure also contained strong involvement of the municipal police
and involved appointing new officers for strict surveillance of
access. Strong public and institutional supports enabled the local
government to plan and implement traffic restriction.
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Barcelona Access Control: Poble Sec and La Ribera,
Spain
Display location
The case studies in Barcelona were reported in one of the successful
GAUDI (Generalised and Advanced Urban Debiting Innovations) project. Vera
et al (1993) report the first of the Barcelona experimentations Poble
Sec, and Hayes et al (1995) and Miles et al (1998) summarized the impact
of access control systems and tools applied in some cities, including
Barcelona.
Context
Poble Sec scheme during Olympic Games from 25 July 1992 to 9 August 1992
was to protect a residential neighbourhood from visitor car traffic attempting
to park near the place of the main Olympics events and serve to promote
the usage of public transport. In this scheme, residents and other authorized
vehicles were provided with permits for entry to the zone during the period
of the Olympics. Many of the access streets to the restricted zone were
closed, and access control applied to the remaining four entry points.
The scheme was based on manual enforcement with the registration of automatic
tag transactions to reduce the task of validating identifiers. The control
measures were imposed to from 10 am to 10 pm.
The second access control experimentation in the La Ribera scheme has
been started from January 1995. The scheme focused on the promotion of
street space for pedestrians and other non-vehicle users. Only authorized
vehicles were permitted to gain access and the configuration incorporated
a retractable bollard to prevent unauthorised vehicles from entering.
Vehicle owners received authorisations on smartcards which were inserted
into on-board units which communicated with roadside equipment. Entry
points for the scheme have been located on the secondary road network
where traffic intensities are low enough for a bollard-based enforcement
solution to be considered. The bollard control was employed clearly to
promote the concept of pedestrian priority in a way that serves to calm
traffic. Enforcement hours are peak hours: 11 am to 2 pm and 5 pm to 8
pm. In 1996, the La Ribera scheme was extended to provide priority access/loading
space for delivery vehicles, possibly in association with parking services.
Implementation size of Poble Sec and La Rivera is a following table:
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Poble
Sec
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La Ribera
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Inhabitants inside controlled zone
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37,042
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4,500
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4+ wheeled vehicles inside zone
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12,895
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2,300
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Daily vehicle entries prior to scheme
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24,000
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2,860
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(Hayes et al, 1995)
Impacts on demand
In Poble Sec scheme, a total average daily traffic of 16,106 vehicles
was recorded entering the zone during this period. This compares with
a total volume of 24,131 per day which entered the zone on a weekday in
July prior to the introduction of the restrictions. This indicates a reduction
in demand of 33% with respect to the conditions experienced in the zone.
Following table summarises the average travel time and delay savings compared
with the normal July situation. Both average travel time and delay savings
were reduced during the period of implementation.
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Before
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During-July
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During-August
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Average route journey time
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19'54"
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17'02"
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16'02"
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Reduction
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11%
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16%
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Average delay per route
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2'54"
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2'23"
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2'12"
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Reduction
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18%
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24%
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(Vera et al, 1993)
In La Ribera scheme, during the hours of access restriction at the main
entry, the volume of vehicle entries is reduced by 90%. Whilst during
times of unrestricted access results in a 78% reduction over working day.
The analysis of before-and-after on-street parking showed that occupancy
levels have increased during the morning hours prior to the restriction
both inside and outside the zone. (Hayes et al, 1995 - This result does
not make clear the time of "before-and-after"). Although residents
perceive a reduction in traffic congestion inside the zone, delays in
the zone were negligible both before and after. The border area also shows
no significant change in journey time. Both La Ribera residents and visitors
report reductions in private vehicles, overall reductions of 24% and 20%
respectively, and increased in the use of public transport and walking
and cycling (Hayes et al, 1995).
Impacts on supply
Road capacity has been maintained, but access control gates were installed
with Automatic Vehicle Identification (AVI) technology. In the La Ribera
scheme at the first principal entry site, space at the junction was sufficient
to enable an island to be introduced so as to separate vehicles wishing
to enter from the rest of the circulating traffic.
Contribution to objectives
Contribution to objectives
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The economic efficiency of AVI control technology was shown to
compare favourably with manual methods using police. However, the
unchanged congestion will have decreased efficiency because of payment
of cost.
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Poble Sec scheme can be effective in safeguarding residential
areas from being overrun by the private car traffic that is attracted
to major events.
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No estimation has been made, but the reduction of congestion will
have reduced air and noise pollution inside zone.
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Improvements in public transport have made the transport environment
more equitable and reduced the potential for social exclusion through
lack of access to a car.
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By reducing congestion, increased speeds may increase a number
of accidents. However, if the low average speeds still remain, the
number of accidents will not rise.
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No analysis has been conducted, but the reduction of congestion
will have reduced associated costs to the economy.
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AVI technology was set in several entry gates, but with little
financial investment.
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Residents living inside the controlled zone expressed high levels
of satisfaction with the measures in both Poble Sec and La Ribera.
Social acceptance needs to implement these schemes on a permanent
basis.
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Sao Paulo Number Plate Restriction: Rodizio, Brazil
Display location
Context
A number plate restriction program called "Rodizio" in Sao Paulo
is reported by Biezus and Rocha (1999). CETESB (Companhia de Saneamento
Basico do Estado de Sao Paulo - Sao Paulo State's environmental agency)
conducted by surveys in the city centre area, using the amount of carbon
monoxide in the atmosphere as indicator, showed that during the five year-period
(1992-1997) only in 36% of the winter days the air quality was considered
good. To tackle this problem, CETESB enforced Rodizio in 1995. Also, the
City Administration started a similar initiative from 1997.
The two type of Rodizio's scheme are as follows, (a) CETESB and (b) City
Administration:
Area covered: (a) Part of the Sao Paulo Metropolitan Region
(10 municipalities of the Greater Sao Paulo)
(b) The centre of Sao Paulo (area within the inner ring road)
Enforcement period: (a) July to September
(b) February to June and October to December
Restrictions in force: 20% of the licensed vehicle fleet for each workday.
The restriction is based on the last digit of the number plate. Every
working day corresponds to the restriction of two digits. For example,
Monday prevent the circulation of cars whose number plates have as its
last digits either 1 or digit 2. The restriction date is shifted every
month.
Hours of enforcement: (a) Working time: 7 am to 8 pm.
(b) Peak hours: 7 am to 10 am and 5 pm to 8 pm.
Impacts on demand
CET (The city's traffic management agency) conducted a survey of traffic
volume in peak time at seven important avenues of the city between October
1997 and March 1998. The result was a reduction in the hourly volume of
2% during the AM peak and 5% during the PM peak during the Rodizio comparing
before the adoption of it. CET also conducted a field survey to monitor
traffic performance on two major city avenues during the same period.
The following table indicates the improvement in both travel time and
the average speed.
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Before the Rodizio
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During the Rodizio
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Change
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Travel time
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Morning
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21'27"
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17'37"
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-18%
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Afternoon
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22'46"
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18'42"
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-18%
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Average Speed
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Morning
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18.6 km/h
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22.8 km/h
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23%
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Afternoon
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17.5 km/h
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21.6 km/h
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24%
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(Biezus and Rocha, 1999)
CET developed the concept of CQL (Congestion Queue Length), implemented
from 1991 to quantify traffic congestion. The measurement is based to
the empirical distinction between traffic categories: free-moving, slow,
stop-and-go and standing still. The CQL is defined by the sum of the queue
lengths of the latter three categories. Average CQL during the Rodizio
was 37% in AM peak and 26% in PM peak lower than before the adoption of
it. The reduction for the period between 7 a.m. and 8 p.m. was 17.7%.
Modal spirit in the Sao Paulo metropolitan region tends to increase the
share of car use, adversely to decrease the public transport share during
last two decades. The changes in the modal split are that the share of
public transport reduced from 45.6% (in 1977) to 33.4% (in 1997), the
car rose from 29.1% to 32.2%, while pedestrian trips also rose from 25.2%
to 34.3%. The Rodizio period covered the years of 1996 to 1998 showed
a consistency with same tendency of the last decades. This means that
this phenomenon outweigh the Rodizio. As the volume of licensed vehicles
continued to grow a same rate after implementation of Rodizio, Biezus
and Rocha (1999) have some concerns that the permanent adoption of the
Rodizio will lead to an additional car for each household with a different
number plate.
Impacts on supply
There is no change to the supply of road space. The number of trips by
buses was reduced by 5% by controlling the excess bus supply provoked
by congestion which is represented by additional vehicles in the bus fleet.
Contribution to objectives
Contribution to objectives
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The reduction of congestion (CQL) resulted in an increase in average
speeds and a decrease in travel time. There were substantial reductions
in congestion costs and increases in benefits.
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No analysis has been conducted, but the reduction of congestion
should cause improved liveability.
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The carbon monoxide amount released by vehicles reduced the occurrence
of negative and inadequate atmospheric conditions from 14.7% to
3.9%.
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No assessment of equity impacts has been made, but those making
occasional journeys off peak during enforcement hours will have
benefited.
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By reducing congestion, increased speeds may increase a number
of accidents. However, if the low average speeds remain, the number
of accidents will not rise.
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No analysis has been conducted, but the reduction of congestion
will have reduced associated costs to the economy.
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There is no evidence regarding costs, but it is thought that local
government needs to pay surveillance costs for checking the validity
of number plates.
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Nor reported, but it is thought that local government needs to
establish a new air pollution control law.
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Gaps and weaknesses
A number of European cities implement a similar scheme of permit systems.
More than 40 cities have introduced traffic-limited zone in Italy (Topp
and Pharoah, 1994). Although some local governments or researchers published
the report of the evidence relating to impacts, these reports include
only the impacts in the short or middle term. There are gaps in our knowledge
of long-term impacts despite those most cases have been continued to enforce.
The impact of regulatory restrictions will be potentially likely to erode
during long term. Continued effort is needed in the long term.
Permit systems are usually implemented as one of mixed car use restrictions
instruments, so that this could explain the lack of up to date knowledge
relating to permit systems as an independent measure.
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