Context: Software process improvement (SPI) is one type of innovation often formulated to address problems such as uncontrollable costs, schedule overruns, and poor end product quality. This study investigates SPI through the application of knowledge management (MM) at the software project level, viewing MM, when applied in software development, as complementary to SPI. Objective: This study advances the use of MM in SPI by investigating impediments to the use and flow of knowledge within an individual software development project. Our proposition is that the removal of obstacles to project-level knowledge flow (K-flow) will enhance SPI. We investigate this proposition by exploring the problems associated with project K-flows as seen by software project team members. Method: We conducted a descriptive case study of an industrial software development project, in which we collected data concerning project knowledge sources and K-flows using semi-structured interviews. Using this data, we constructed a diagnostic project knowledge map (K-map). The K-map was analyzed to identify K-flow obstacles and potential solutions. Questionnaires based on these obstacles and solutions were formulated to probe software engineers' perceptions of the effect of the solutions on SPI. Results: Findings from participant questionnaires reveal that software engineers perceive that the removal or mitigation of project-level K-flow obstacles generally reduces the time to perform their work, helps them to meet their deadlines, and improves their work quality, thus resulting in SPI. Conclusions: This study provides support for the usefulness of project-level K-flow obstacle removal for SPI. It provides a unique project-level perspective, using input from the project's software engineers. It also explains and supports the use of K-mapping for the identification of project-level K-flow obstacles. With this approach, practitioners gain insight into SPI in "real time" as a project is executed. These insights may help to enhance their current and future SPI efforts. (C) 2015 Elsevier B.V. All rights reserved.