Margherita Cadei on "The Urban Road Safety Plan (PSSU):the case study of Brescia"

1. Cagliari, 10-12 maggio 2012
The Urban Road Safety Plan
(PSSU): the case study of Brescia
Eng. Margherita CADEI
PhD student in “Places and times of the city and territories”
University of Brescia
Faculty of Engineering - DICATA
margherita.cadei@ing.unibs.it

2. INTRODUCTION
Urban Road Safety Plan (Piano Della Sicurezza Stradale Urbana – PSSU) has been
introduced in Italy in 2001
(Ministry of the Public Works Circular n.3698 “Piani della sicurezza stradale urbana –
Linee guida per la redazione”, Rome, June 8th 2001)
BRESCIA (Middle-sized city; population: about 200.000 people; surface: about 90
km2)
First PSSU elaborated in 2009
PSSU: a planning tool to manage road
safety at local level (urban areas) in an
organic and systemic way.
Based on road accident data analysis, it is
able to detect the road accident problems
on the urban road network and to offer
objective criteria to make choices.
Before: decisions about road safety based
on extemporary choices or warnings coming
from the population.
INPUT 2012 – Cagliari 10-12 may 2012 Eng. Margherita Cadei – University of Brescia

3. A PSSU’s main document (Piano Direttore) contains:
- aggregate analysis of the road accident data;
- detection of the network “Black spots”;
- definition of quantitative objectives and list of actions/strategies to be implemented;
- quantification of costs/benefits;
- definition of the monitoring process and coordination of the plan.
One of the most important purpose of a PSSU consists in making lists of critic
sites where infrastructural interventions are more urgent (“Black spots”).
It’s important to use adequate indicators to express the level of risk of the
network segments.
INPUT 2012 – Cagliari 10-12 may 2012 Eng. Margherita Cadei – University of Brescia

4. A PSSU’s main document (Piano Direttore) contains:
- aggregate analysis of the road accident data;
- detection of the network “Black spots”;
- definition of quantitative objectives and list of actions/strategies to be implemented;
- quantification of costs/benefits;
- definition of the monitoring process and coordination of the plan.
One of the most important purpose of a PSSU consists in making lists of critic
sites where infrastructural interventions are more urgent (“Black spots”).
It’s important to use adequate indicators to express the level of risk of the
network segments.
INPUT 2012 – Cagliari 10-12 may 2012 Eng. Margherita Cadei – University of Brescia

5. A PSSU’s main document (Piano Direttore) contains:
- aggregate analysis of the road accident data;
- detection of the network “Black spots”;
- definition of quantitative objectives and list of actions/strategies to be implemented;
- quantification of costs/benefits;
- definition of the monitoring process and coordination of the plan.
One of the most important purpose of a PSSU consists in making lists of critic
sites where infrastructural interventions are more urgent (“Black spots”).
It’s important to use adequate indicators to express the level of risk of the
network segments.
In Brescia: ROAD ACCIDENT RATE (for each “homogeneous road segment i”):
10 6 ⋅ N i
Ti =
365 ⋅ l i ⋅ ∑ TGM i,t
t
INPUT 2012 – Cagliari 10-12 may 2012 Eng. Margherita Cadei – University of Brescia

6. Instead of calculating the road accident rate for road segments belonging to single
itineraries and instead of comparing the segments’ rate with two threshold values
(CNR,1998) in Brescia each road segment rate is compared with the average
value calculated for the road functional class to which the road segment belongs
(Maternini, 2000).
Id Road segment Ti
This indicator is able to express the risk related to
21 VIA MILANO 2,71
road safety: it puts into relation the number of
44 VIA CROCIFISSA 2,38
accidents, the road segment length and the amount
35 VIA ZIMA 2,34 of traffic.
50 P.LE SPEDALI 2,32
13 VIA CHIUSURE 2,30 FAULTY ASPECT: Inaccuracy inherently contained
49 VIA DAL MONTE 2,26
in the Istat road accident data (Tiboni, 2004)
20 VIA MILANO 2,23 The exact localization is not always possible;
40 V.LE PIAVE 1,94
… … … Uniform distribution of the incomplete data!
INPUT 2012 – Cagliari 10-12 may 2012 Eng. Margherita Cadei – University of Brescia

7. SOME CRITICALITIES ABOUT THE ELABORATION OF THE PSSU:
ENDOGENIC FACTORS EXTERNAL FACTORS
- quality of the Istat road accident data: - PSSU is just a “mandatory task”: it
- imprecise mapping introduces a is elaborated but not actually
systemic error in the road accident implemented;
rate calculation;
- late delivery of the Istat data - lack of a strong policy towards the
makes unfeasible the monitoring of road safety issues:
the actions (PSSU life time spans 2 - inadequate resources
years) assignment for the
- disaggregate analysis implementation plans;
methodologies based on road - scarce coordination among
accident scenarios/collisions the technical departments in
diagrams cannot be easily applied delivering the road safety
projects/plan updating
- the Ministry Guidelines are, in some
parts, vague/incomplete:
- cost/benefit analysis;
- the “participated plan process” is
not sufficiently promoted
INPUT 2012 – Cagliari 10-12 may 2012 Eng. Margherita Cadei – University of Brescia

8. SOME CONCLUSIONS
There are still some aspects that makes road safety planning/implementation
difficult;
it is hoped a wider application of the good practices available in
literature/resarches in this field;
it is hoped a review/enhancement of the present Ministry guidelines;
a stronger integration between the road safety and the already existing
urban/mobility planning tools should be promoted.
INPUT 2012 – Cagliari 10-12 may 2012 Eng. Margherita Cadei – University of Brescia

9. Cagliari, 10-12 maggio 2012
:: Thank you for your attention ::
The Urban Road Safety Plan (PSSU):
the case study of Brescia
Eng. Margherita CADEI
PhD student in “Places and times of the city and territories”
University of Brescia
Faculty of Engineering - DICATA
margherita.cadei@ing.unibs.it