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C H A P T E R 6 Data Provisioning The primary data-sharing concern will be to ensure that the Role-based security has successfully demonstrated its abil- consent form language clearly states the conditions under ity to cover a range of access requirements. Different roles which the data may be shared after the study is complete. The can be defined to have different security access as appropri- language should spell out whether the data to be shared will be ate. Security can be defined in terms of row-level access (e.g., identifiable and the conditions for each type of data sharing. where a user has access to all the data within a given region), Data-sharing agreements may be needed for identifiable data column-level access (e.g., where a user may have access to all but will likely not be needed for de-identified data that are the data except GPS location information), or a combination publicly available. However, some form of IRB approval may of the two (e.g., cell-level access where a user may have access still be required for all data access. The terms of this data to GPS location data within a specified region). It should be access are still being determined as of this report date. noted that this security protocol provides protection to both database and file-based (e.g., video) data, as illustrated in Figure 6.1. Data Dictionaries To assist all researchers, data dictionaries are being developed Required Software that will identify each data item (or data stream) collected dur- ing the study. These data dictionaries include operational def- It is generally expected that most external access will be pro- initions as well as database references. These may be especially vided through a website or web service. However, provisions helpful for those not involved in the original data collection. will be in place to allow qualified users to obtain their access Additionally, it is anticipated that custom data dictionaries via direct file server or database server access using the role- will be necessary to support data located through research- based access described previously. For example, in these cases, specific queries. Specifically, if new operational definitions are remote users may be able to obtain access through the use of used to develop new variables, the definition and the approach typical Virtual Private Network (VPN) technologies. Using a must be documented both for the original researchers looking role-based approach as defined accommodates and supports at these data and for future researchers. the use of a website/service to provide general data access. As such, commercially available data analysis tools (e.g., SAS and Matlab) can be used by researchers interested in con- Role-Based Access ducting analysis on the data. A shareware-based Community The ability to provide scalable user access control to the com- Viewer will be provided also, but no specialized proprietary bined data sets that will be collected and generated in the software will be required. course of the study is governed by a role-based security pro- tocol and is dependent on the researcher requesting the data Coordination and Linking with successfully obtaining IRB approval. Role-based security pro- Roadway Information tocols authorize access to data elements based upon explicit security roles that users may be granted. Without any assigned SHRP 2 Safety Project S04A, Roadway Information Database roles, the default authorization granted to users who success- Development and Technical Coordination and Quality Assur- fully "authenticate" (successfully log in) is to deny access to ance of the Mobile Data Collection Project, and Safety Project any secured data. S04B, Mobile Data Collection, will provide valuable roadway- 28
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29 S06: O&I Contractor Data Decryption Making Data Normalization Aggregation Maintenance Accessible O&I Video Processing Processes Data generation algorithms Data for Creating reduced databases Access Etc. Data for Access by Users based on Roles & Permissions Role-Based Data Access Permissions Possession of Temporary all relevant Access to all Access to Access to watermarked relevant data & relevant de-ID'd aggregated, data & uncensored data & video de-ID'd data; uncensored video no video video Yes Yes Yes Yes Data User Roles Limited Access Data possession Full Access by IRB No No by IRB No General Public by IRB Approval? Approval? Approval? External Data Users Figure 6.1. Role-based data access diagram. based data describing in detail sections of roadway traveled measured in length along the traveled roadway path from this by the instrumented vehicles included in the NDS. Roadway zero point. Vehicle data are generally located geographically data will be extracted from existing inventory databases main- using latitude, longitude, and sometimes elevation, collected tained by state and local transportation departments and throughout a vehicle trip. Roadway inventory data collected supplemented with other inventory data collected by highly by instrumented vans can be located in either fashion--either instrumented on-road data collection vans. Successful inte- as a distance from a zero point or geographically. Integration gration of these two data sets will support many research of these data will require transformation of one or both types questions that involve the interaction between the driver, of data to determine at what position in the roadway data the the vehicle, and the roadway and appurtenances. Recogniz- vehicle is during travel on a measured roadway. Communica- ing that these two efforts will be executed somewhat inde- tion between S03 contractors and NDS contractors has been pendently but simultaneously, actions have been taken in conducted to determine what will be required to make these advance to ensure that integration of these data sets will be transformations and what adjustments may be required during possible and feasible so as to support the desired research. data collection to support these transformations. A GPS mea- Roadway inventory data in currently existing files are gen- sure would be required at each zero point but, though valu- erally specified using a zero point; subsequent stations are able, it may not be required at subsequent stations. Vehicle
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30 GPS data can be used to identify when the vehicle passes a effort. In this way, segments that can provide replications to zero point, and then vehicle speed and time data could be support research will be identified and provided to the S04 integrated to estimate when the vehicle passes subsequent contractors to guide collection. On the basis of investigation stations. The degree of accuracy of candidate approaches will of previous naturalistic data collections (Dingus et al. 2006), be evaluated as they are identified. these high-frequency locations are generally coincident with Collection of roadway data will not be feasible on all road- high-volume corridors within a study area and places of ingress ways on which NDS participant vehicles travel. To priori- and egress to these corridors and also highways. The accumu- tize the measurement of roadway segments, NDS data will lating actual naturalistic data will be used to narrow these gen- be processed regularly to identify roadway segments that are eral rules to determine the specific segments traveled frequently traveled frequently by more than one participant in the NDS by several participants.