You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: Pedestrian Protection Systems: Issues, Survey, and Challenges 
Chapter Title:  F. Representative Systems for Pedestrian Protection 
1. Abstract of Cited Paper (BIB001):  This paper presents a multi-cue vision system for the real-time detection and tracking of pedestrians from a moving vehicle. The detection component involves a cascade of modules, each utilizing complementary visual criteria to successively narrow down the image search space, balancing robustness and efficiency considerations. Novel is the tight integration of the consecutive modules: (sparse) stereo-based ROI generation, shape-based detection, texture-based classification and (dense) stereo-based verification. For example, shape-based detection activates a weighted combination of texture-based classifiers, each attuned to a particular body pose. ::: ::: Performance of individual modules and their interaction is analyzed by means of Receiver Operator Characteristics (ROCs). A sequential optimization technique allows the successive combination of individual ROCs, providing optimized system parameter settings in a systematic fashion, avoiding ad-hoc parameter tuning. Application-dependent processing constraints can be incorporated in the optimization procedure. ::: ::: Results from extensive field tests in difficult urban traffic conditions suggest system performance is at the leading edge.

Literature Review:
The European Commission funded projects PROTECTOR (preventive safety for unprotected road user) and its extension SAVE-U (sensors and system architecture for VRUs protection) were established for developing systems for enhancing pedestrian safety. Two car manufacturers Volkswagen and DaimlerChrysler had worked on this project to develop pedestrian protection systems. The DaimlerChrysler's research system is described in BIB002 , which builds on their earlier research in BIB001 . This system combines pedestrian detection, trajectory estimation, risk assessment, and driver warning. It uses a pair of visible light sensors in stereo configuration and combines multiple algorithmic stages to dramatically reduce the false alarm rate while keeping reasonably high detection rate. The system consists of the following modules.