Mobile Mapping System: case study of the Messina-Palermo motorway layout

This paper presents the first results of the MMS (Mobile Mapping System) survey on the geometry of the A20 italian motorway Messina-Palermo. The layout parameters are the essential data for an effective management of a single or a road network. In particular these parameters are essential for applying the Design Consistency methodology to proposed or existing road infrastructures; through this methodology the road manager can make sure that the road characteristics are adjusted to the driving behaviour of motorists by analysing the relationship between horizontal and vertical alignment and the design and operating speed. Both the difficult finding of the road design schemes, particularly in regard to the oldest roads, and the difference between the design layout and the observed layout lead to carry out an experimental survey on the road layout. This work was to aim to investigate by kinematic GPS techniques the layout of three sites of A20 Messina-Palermo motorway, using a network of permanent stations. For each site, the authors set up the geometry of horizontal and vertical alignment (known or unknown) using a specific road design software. The three sites are located in two areas near Messina, Calderà and Bazia, and characterized by a planimetric sequence tangent-spiral transition-circular curve. In the early stage of this work, for all the sites listed above, we have examined the planimetric schemes (scale 1:2000) that were lacking in geometric data (radii and lengths of circular curves, parameters of spiral transition curve), while the vertical alignment schemes were not available.