  The advancement of mobile technologies and the proliferation of map-based
applications have enabled a user to access a wide variety of services that
range from information queries to navigation systems. Due to the popularity of
map-based applications among the users, the service provider often requires to
answer a large number of simultaneous queries. Thus, processing queries
efficiently on spatial networks (i.e., road networks) have become an important
research area in recent years. In this paper, we focus on path queries that
find the shortest path between a source and a destination of the user. In
particular, we address the problem of finding the shortest paths for a large
number of simultaneous path queries in road networks. Traditional systems that
consider one query at a time are not suitable for many applications due to high
computational and service costs. These systems cannot guarantee required
response time in high load conditions. We propose an efficient group based
approach that provides a practical solution with reduced cost. The key concept
for our approach is to group queries that share a common travel path and then
compute the shortest path for the group. Experimental results show that our
approach is on an average ten times faster than the traditional approach in
return of sacrificing the accuracy by 0.5% in the worst case, which is
acceptable for most of the users.
