Design a safe bike lane.

In the Bike Lanes task, a city is encouraging its citizens to use bicycling as a form of transportation. Students need to apply the engineering design process to come up with a route design for a safe bike lane. Similar to what engineers face when tackling a problem, students need to produce a design that meets specific requirements while accounting for trade-offs between options including cost and safety.

Content Area: Design and Systems
Practice: Developing Solutions and Achieving Goals
Learn about content areas and practices
Task Time: 18 minutes
Assessment Year Used: 2014

Most students understood the requirements for a final design but were less able to carry out a design process and explain a design rationale involving trade-offs between solutions.

76%
of students were able to identify the requirements for a design.
45%
of students successfully carried out a design using trade-offs to choose between alternative solutions.
11%
of students were able to communicate a design rationale that clearly explained the role of trade-offs in their design decision.
Explore task details by selecting a step below
Step 1
Learning About Design Criteria
Determine how lane width and speed limit affect road safety.

76% of students were able to fulfill the criteria for designing a safe bike lane.

What Students Did

Students learn about the criteria for a well-designed bike route that allows cars and bikes to safely share the road. They use an interactive tool to adjust lane width and speed limit to select which combinations of factors will produce a safe bike lane.

Skills Measured

  • Redesigning or modifying an existing system to address a need.
  • Carrying out a design process to solve a problem by identifying criteria and constraints for the final design.

Student Performance

76% Complete
All four correct selections made
17% Partial
Three correct selections made
7% Unsatisfactory
Two or fewer correct selections made

Related Experience from Student Survey

71% of Students
reported learning about designing or creating something to solve a problem, in school, at least sometimes.
Step 2
Explaining the Design Criteria
Explain trade-offs among design criteria.

48% of students were able to explain the trade-offs among the safety requirements for a well-designed bike lane.

What Students Did

Students complete a data table showing the safety of roads with different combinations of speed limit and lane width. They need to use the data as evidence to support their explanation of how the trade-offs between speed limit and lane width could affect cyclist safety.

Skills Measured

  • Redesigning or modifying an existing system to address a need.
  • Carrying out a design that involves considering trade-offs to choose between alternative solutions.

Student Performance

48% Complete
Response describes the effect of both lane width and speed limit on safety
33% Partial
Response describes the effect of lane width or speed limit on safety
19% Unsatisfactory
Response does not describe the effect of lane width or speed limit on safety

Related Experience from Student Survey

37% of Students
reported building or testing a model to see if it solves a problem, outside of school, three or more times.
Step 3
Planning for a Safer Bike Route
Identify route modifications based on design criteria.

64% of students were able to select the relevant design changes needed to make streets safer for cyclists.

What Students Did

In this part of the task, students plan for redesigning the bike route by selecting relevant road modifications that meet the criteria for improving cyclist safety.

Skills Measured

  • Redesigning or modifying an existing system to address a need.
  • Redesigning a system using a reasonable number of relevant modifications.

Student Performance

64% Complete
All four correct selections and no incorrect selections
18% Partial
All four correct selections and one incorrect selection or three correct selections and no incorrect selections
18% Unsatisfactory
Any other pattern of selections

Related Experience from Student Survey

65% of Students
reported using tools or materials to plan or design something, outside of school, three or more times.
Step 4
Redesigning the Route
Propose a design based on criteria and constraints.

45% of students were able to redesign the bike route taking into account criteria and constraints on the final design solution.

What Students Did

Students are informed that the town cannot afford to make all possible street modifications for the new bike route. They use an interactive mapping tool to design the least expensive and shortest possible route. Students need to prioritize cost over route length.

Skills Measured

  • Redesigning or modifying an existing system to address a need.
  • Carrying out a design that involves using trade-offs to choose between alternative solutions.

Student Performance

45% Complete
The cheapest route is selected: AGFE
11% Essential
A compromise route is selected. Example: shorter than AGFE but not the cheapest
29% Partial
Any route with four segments connecting the two neighborhoods
15% Unsatisfactory
Any route that has either less than or more than four segments

Related Experience from Student Survey

50% of Students
reported taking something apart in order to fix it or see how it works, outside of school, three or more times.
Step 5
Providing a Design Rationale
Explain trade-offs among criteria.

11% of students were able to provide a rationale for their design, which included a complete explanation of the compromise among design criteria.

What Students Did

In this section, students need to provide a rationale for their proposed route design. They need to explain how their route design was a compromise between cost and route length.

Skills Measured

  • Redesigning or modifying an existing system to address a need.
  • Providing a design rationale that includes identifying relevant trade-offs among criteria.

Student Performance

11% Complete
Response clearly describes the chosen route as a compromise between cost and length
62% Partial
Response does not acknowledge the compromise between cost and length
27% Unsatisfactory
Response is ambiguous or does not refer to the design criteria

Related Experience from Student Survey

52% of Students
reported learning about designing something when there is limited time, money, or materials, as part of their school work, at least sometimes.
A Closer Look: How Students Solved a Design Problem by Evaluating Trade-Offs Between Alternative Solutions
Five percent of students could identify relevant design changes, account for design trade-offs, and explain a design decision as being a compromise between trade-offs.

Follow the left-most series of blue disks.

Task Step 3 (Question 3): Identifying necessary design changes.

64% of students could select the relevant design changes needed to make streets safer for cyclists.

Task Step 4 (Question 4): Carrying out a design using trade-offs among alternative solutions.

35% of students could select relevant design changes and successfully redesign a bike route taking into account the trade-offs between cost and distance in the final design.

Task Step 5 (Question 5): Explaining the reasoning behind a design decision.

5% of students could select relevant design changes, account for design trade-offs, and explain a design decision as being a compromise between trade-offs.

Chart with 2 disks.  On left, blue disk indicating 64% correct. On right, disk indicating 36% partially correct/unsatisfactory.
Chart with 4 disks.  From left to right: Disk indicating 35% correct, disk indicating 29% partially correct/unsatisfactory, disk indicating 10% correct, disk indicating 26% partially correct/unsatisfactory.
Chart with 12 disks. From left to right: Blue disk indicating 5% correct, disk indicating 30% partially correct/unsatisfactory, disk indicating 3% correct, 26% partially correct/unsatisfactory, disk indicating 2% correct, 9% partially correct/unsatisfactory, disk indicating 1% correct, 25% partially correct/unsatisfactory.