a reasonable suspicion. Current information about daytime residential break-ins in the area where the van and its occupants
were seen twice within a week. The apparently random nature
of their driving pattern.
 In addition, the respondent continues, a sufficient HTA
purpose animated this stop: the need to confirm that the occupants were in lawful possession of the vehicle and lawfully
licensed and insured to operate it. This invoked the dual purpose
doctrine relied upon by the trial judge.
The governing principles
 Several principles have a say in an assessment of this
ground of appeal.
 First, the Charter guarantee against arbitrary detention.
 The purpose of the guarantee against arbitrary detention
in s. 9 of the Charter is to protect individual liberty from unjustified state interference: R. v. Grant,  2 S.C.R. 353, 
S.C.J. No. 32, 2009 SCC 32, at para. 20. Absent a law to the
contrary, individuals are free to do as they please. On the other
hand, the police, more broadly the state, may act only to the
extent that the law empowers them or it to do: R. v. Mann, 
3 S.C.R. 59,  S.C.J. No. 49, 2004 SCC 52, at para. 15.
 A law, whether originating in a statutory enactment, the
common law or some combination of sources, may authorize and
prescribe the limits on a detention. Provided the detention is at
once authorized by law and does not exceed any limitations the
law imposes upon it, the detention is lawful and thus not arbitrary within s. 9 of the Charter: Mann, at para. 20.
 In approaching a complaint of arbitrary detention, a court
should consider first whether some lawful authority sanctions
the detention, then, if permitted, whether the detention falls
within or beyond any applicable limits on that authority.
 In this case, the trial judge concluded that the detention
was lawful under s. 216(1) of the HTA, even though the primary
motivating factor was Det. Ward’s pursuit of his investigation of
the daytime, residential break-ins in the area. Accordingly, it is
necessary to consider whether the detention falls within the
scope of s. 216(1) of the HTA.
 Section 216(1) of the HTA authorizes a police officer to
stop vehicles for highway regulation and safety purposes, even
where the stops are random: Brown v. Durham, at para. 21; R. v.
Ladouceur,  1 S.C.R. 1257,  S.C.J. No. 53, at p. 1288
S.C.R.; R. v. Simpson (1993), 12 O.R. (3d) 182,  O.J.
No. 308, 79 C.C.C. (3d) 482 (C.A.), at p. 492 C.C.C. This detention is circumscribed by its purpose. It is limited to the roadside.