■ Choice of optimal route based on the level of safety 
and time to cover the distance; 
■ Legal-administrative state of the road; 
■ Plan for the management of work and work being 
carried out, 
• Traffic monitoring positions; 
■ accidents; 
■ turn-offs; 
■ concession works (aqueducts, cables, etc.). 
The principle aims of the survey are: 
□ the planning of work and investment, in as much as 
they give all the information relative to the situation 
of the road network, in terms of traffic, accidents, 
etc., the progression of work and projects and 
environmental impact; 
□ the management and maintenance of the roads 
and the relative competence, in as much as it 
contains point information and details relative to the 
single stretches; 
□ the planning and management of traffic 
(management of exceptional loads, alternative 
routes, monitoring). 
4.2. The experience of the European Economic 
Community (E.E.C.): the R.I.M.E.S project. 
The domains of work considered in the R.I.M.E.S. 
project are: 
■ road networks 
■ traffic 
■ maintenance 
■ instruments 
■ pavement 
■ works 
■ accidents 
■ work in progress 
■ costs and financing 
■ geometry. 
The domain of the road network allows the graphical 
positioning, by means of the co-ordinates of a system of 
“global” reference, the objects that belong to the road 
network along the stretch to which they belong. 
The data of the R.I.M.E.S. project can be placed into 
four categories: 
1) the definition of the road network; 
2) data that change according to the decisions of the 
Authority (e.g. a road illumination project); 
3) data that change due to road aging (e.g. loss of load 
bearing and unevenness); 
4) data that change in a random way (traffic and 
accidents). 
The data of the first and second categories can be 
acquired once and amended only with administrative 
procedures, while all the other data must be acquired 
and corrected by means of continual monitoring along 
the road network. 
The connection between the various databases o 
between information systems can be assured in the 
following ways: 
■ with a common system of road geo-referencing; 
■ by means of digital maps; 
■ by means of connective networks. 
5. APPLICATION OF G.P.S. TO ROAD SURVEYS 
The exact knowledge of the geometry of the 
infrastructure is a preliminary condition that is 
necessary for the functional classification and the 
realization of a road cadastre. 
The attribution of classification parameters, such as the 
deign speed, the level of service or the allowed traffic 
flow, is based, in fact, on the plano-altimetric 
characteristics of the road axes and on the composition 
and geometry of the transversal section. 
Traditional cartography, as is easy to verify, does nor 
allow, if not with great approximation, the extrapolation 
of the numeric values of the point curvature of the axes 
or of the longitudinal inclination, which are the first 
elements with which we can determine the maximum 
velocity and the conditions for road safety. 
Numeric cartography, of which the territorial authorities 
are slowly beginning to use, also due to the ever 
increasing need to have proper Territorial Information 
Systems, gives much useful information for a correct 
and complete classification of the road infrastructure. 
However, a complete national coverage and the 
“connection” between all the various maps requires, 
apart from the cost, a length of time that is surely not 
compatible with the immediate needs to have an 
ordered and detailed classification of the entire national 
road network, which extends for about 300,000 Km, and 
to institute a road cadastre. In any case, the survey of 
the road infrastructure is necessary to update the 
existing maps. 
In this view there is also the possibility of using a GPS 
system for the rapid surveying of the road network with 
a level of detail and precision compatible with the 
functional classification. For some years now 
experimental research has been carried out to verify the 
adaptability of the system of satellite navigation for the 
needs of road surveying. The first surveys, carried out 
with a single GPS receiver mounted on a vehicle in 
movement along a road, showed metric precision 
comparable to cartographic data. 
With the use of differential techniques, that is using two 
receivers, one fixed and the other on the moving 
vehicle, today it is possible to reach centimeter 
precision, which allows for the determination of macro 
deformations and superficial irregularities. 
It must be underlined, however, that the GPS, alone, 
does not resolve the problem of road surveying. The 
use of GPS, in fact, is not always possible and, in many 
cases, does not give the above mentioned precision. 
It appears useful, therefore, to synthetically lay out the 
problems connected to the use of GPS in the field of 
road surveys, in order to correctly and realistically 
define the possibilities of its application. 
5.1. Methods of useable surveying 
The centimetric precision is surely sufficient and 
compatible with the needs of the survey and of the 
representation on a large scale (1:2000, 1:1000). 
Obtaining this precision is only possible by the use of 
differential techniques, which allow for the elimination of 
systematic errors that disturb the measurements and, 
above all, the effects of the Selected Availability. 
The kinematic method allows the surveying with 
continuity of the trajectory of the vehicle on which it is 
mounted. Travelling along the road in both directions on 
the axis of the carriage-way, a double trace is 
generated (one for each carriage-way) that can be 
referred to the road axes by interpolation with a 
polynomial line of the B-spline type.