Passage of vehicles across the links between IoT-devices severely hampers low-power communication activities. In an urban area, deployment of an IoT-edge system, hence, gets heavily affected because of the traffic-congested roads. In order to achieve reliable delivery despite the presence of such vehicular obstructions, the IoT-devices need to make multiple repeated transmissions at the link layer or even frequently change the communication path in the network layer. However, such actions significantly drain the energy in the IoT-devices and shorten their life-span. This serious issue, although has been pointed out in several works, has not been yet addressed seriously from the point of view of the mitigation of the problem. In this work we first provide a detailed study of the dynamics of the traffic affected links. Next, we propose a lightweight sensor-assisted data-collection strategy SenseCollect, which first classifies the time periods as bad and good based on the presence and absence, respectively, of the vehicular congestion across the communication links. Furthermore, the strategy takes a delay tolerant approach which exploits the good period, i.e., when the vehicular congestion is comparatively less, for low-power communication more compared to the other (bad) periods. In addition, in order to manage emergency situations we also accommodate scopes for faster and more reliable delivery of the data which are marked as urgent by the corresponding source node. We implement the complete system with the said objectives in the real devices. Evaluation studies depict that SenseCollect achieves data collection with reliability above 99% while saving upto 60% of radio duty-cycle compared to the state-of-the-art strategies when communication links are seriously affected by vehicular traffic.