Object detection is a crucial component in autonomous navigation systems. Current object detectors are trained and tested on a fixed number of known classes. However, in real-world or open-world settings, the test set may consist of objects of unknown classes; this results in the unknown objects being falsely detected as known objects leading to the failure in decision making of autonomous navigation systems. We propose Open World Object Detection on Road Scenes (ORDER) to resolve the aforementioned problem. We introduce Feature-Mix that widens the gap between known and unknown classes in latent feature space and improves the unknown object detection in the ORDER framework. We identify the inherent problems present in autonomous datasets: i) a significant proportion of the dataset comprises small objects and ii) intra-class bounding box scale variations. We address the problem of small object detection and intra-class bounding box variations by proposing a novel focal regression loss. Further, the detection of small objects is improved by curriculum learning. We present an extensive evaluation on two road scene datasets: BDD and IDD. Our experimental evaluations on BDD and IDD shows consistent improvement over the current state-of-the-art method. We believe that this work will lay the foundation for real-world object detection for road scenes.