Designing a car rental app

Simplifying and improving the car renting process for users

The project at a glance.

The product.
A mobile application designed to simplify the car renting process by eliminating clutter and streamlining the booking journey for users.
The problem.
Users frequently feel overwhelmed by cluttered, text-heavy interfaces and unclear terminology, leading to confusion during selection and booking.
My role.
Solo Designer for the end-to-end process—responsible for initial research, market analysis, UI design, and interactive prototyping.
Tools and methods.
Tools: Miro, Figma, FigJam.
Methods: Competitor Analysis, User Journey Mapping, User Flows, Pen-and-Paper Sketching, and Medium-Fidelity Prototyping.
Duration.
2 Months (Accelerated). I condensed a standard 6-month timeline by dedicating 5–7 days of focused execution per design phase.
Understanding the problem.
Before moving into design , I conducted research to uncover user goals, behaviors, and critical pain points.
This discovery phase provided the strategic foundation for every design decision that followed.
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Usability Tests
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Affinity Diagramm
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Journey Map
Usability Test
Fragmented Booking Experiences & Hidden Friction Points
Users often face unexpected hurdles in existing rental apps that disrupt their booking flow

Observing the Booking Journey in Real-Time

I performed a deep dive into the rental market by observing two usability tests on competitor apps
AVIS & Hertz.

I also conducted an original usability test with a target participant. I chose this qualitative method to explore user behaviors in depth and observe friction points as they occurred in real time.

Before moving into design, I conducted research to uncover user goals, behaviors, and critical pain points. This discovery phase provided the strategic foundation for every design decision that followed.
Watch full Usability test videos

Key findings.

Significant transparency and flow efficiency gaps exist even among industry leaders. Real-time friction highlights that simplifying terminology and reducing task sequences is a functional requirement to prevent cognitive load and booking abandonment. Priority must be placed on streamlined navigation to ensure user retention throughout the selection process.
Affinity Diagram
Jargon-Heavy Interfaces and Ambiguous Cost Structures
Users feel overwhelmed by dense blocks of text and often encounter "price shock" due to a lack of clear, upfront cost breakdowns.

Synthesizing Patterns to Reduce Cognitive Load.

Through this affinity mapping, I identified that while the overall booking flow is smooth, users struggle with technical industry jargon and high text density.

Opportunities for improvement include enhancing pricing transparency through clear, itemized cost breakdowns leveraging high-quality imagery to build user trust, reducing unnecessary text, and simplifying the interface to make the booking process as easy and intuitive as possible.
See Affinity diagram

Key findings.

Research through affinity mapping revealed that transparency is defined by the timing and clarity of information rather than just numerical data. Grouping user frustrations confirmed that trust is established by replacing industry-specific jargon with human-centered language.
Journey Map
Opportunities to Clarify & Simplify
Users feel overwhelmed by "information-heavy" pages and lose confidence when faced with ambiguous rental terminology and hidden costs.
See Journey map

Mapping the Pillars of a Streamlined Prototype.

By analyzing the user journey, I identified a recurring pattern of friction caused by cognitive overload and industry-specific jargon. To address these, my design strategy for the prototype will focus on two primary pillars:
■ Simplifying Information Architecture

To solve the "overwhelming" amount of data, I am implementing a progressive disclosure strategy. By utilizing collapsible sections and clear visual hierarchies, I will ensure the interface remains clean while keeping users focused on one decision at a time.
■ Clarifying Terminology and Transparency

I am replacing industry jargon (like CDW and Damage Excess) with plain-language labels and tooltips. Additionally, I will explicitly define mileage costs and the nuances between "Pay Now" and "Pay Later" to eliminate pricing uncertainty.

Key findings.

The journey mapping phase reveals that a "smooth" flow is defined by the mental effort required at each step rather than the absolute number of clicks. Proactively addressing "hidden" questions—specifically by clarifying industry terminology—significantly reduces user anxiety. This strategic reduction in cognitive load prevents drop-offs before users reach the final booking stage, ensuring a more resilient and intuitive conversion path.
Designing the solution.
With a clear understanding of my users and their needs, I began designing a solution that addressed the key pain points uncovered during research. My focus was on creating a car rental booking experience that felt simple, trustworthy, and efficient. I explored different ideas through sketches, wireframes, and prototypes—testing and refining the design based on user feedback at each stage.
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User flow
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Sketching
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Prototype
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Testing
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Iterations
User flow
Establishing Sequential Structure & Flow in the Booking Process
Users often feel lost or hesitant when the path from vehicle selection to final payment isn't clearly defined or logically structured

Architecting a Logical Path to Conversion.

A structured user flow was developed to define the essential steps of the rental booking journey. Mapping the transition from vehicle selection to final payment ensured a logically sequenced architecture before moving into high-fidelity design. This strategic alignment between user intent and task completion ensures that each stage of the journey solves specific friction points while maintaining a clear, direct path to conversion.
See User flow
Sketching
Visualizing Structural Hierarchy and Layout Cohesion
Moving directly into digital tools can lead to rigid designs that fail to address the complexity of text-heavy layouts and transparent pricing.

Iterative Ideation and Layout Exploration.

With the user flow established, I moved into sketching to quickly visualize and iterate on the layout for each stage of the car rental booking process. My focus was on translating the flow into a tangible interface, using pen and paper to explore various design solutions before committing to high-fidelity mockups. This iterative sketching process allowed me to focus on creating an intuitive layout and structure that addresses the user's need for information and transparency.
See full Sketches
Prototype
Refining Interface Structure for Seamless Task Completion
Users often feel overwhelmed when presented with a full list of car specifications and insurance details all at once, leading to decision paralysis during the booking stage.

Iterative Ideation and Layout Exploration.

After refining my sketches, I developed a medium-fidelity prototype to focus on the core functionality and information architecture without the distraction of final brand colors or high-resolution imagery. This stage was critical for validating that the structural changes effectively solved the "low points" identified in the journey map. By building this interactive wireframe, I was able to test the logic of the booking flow and ensure the following UI solutions felt intuitive.

To achieve this, I will implement a progressive disclosure strategy, utilizing collapsible sections and a refined visual hierarchy to significantly reduce clutter. This approach ensures the interface remains visually appealing and keeps the user focused on a single decision at a time, preventing the "information overload" noted in earlier research.

Interactive Prototype:
See Prototype file
Testing
Validating Design Decisions Through Real User Behavior
Even with a structured prototype, users can experience hesitation if the final verification steps or vehicle details do not align with their mental model of a secure booking.

Measuring the Impact of Information Hierarchy.

With the medium-fidelity prototype ready, I conducted usability testing to validate whether my design decisions effectively addressed the pain points found in the initial journey map. I observed how the car rental flow went, specifically looking for signs of "overwhelmed" behavior or confusion regarding terminology. This phase was essential for measuring if the "less clutter" approach actually translated to a smoother user experience.
See full Prototype test video
I analyzed user feedback to evaluate the impact of the medium-fidelity design on perception and trust. Users reported high satisfaction with the linear "A to B" process, noting that the step-by-step guidance is intuitive and successfully reduces cognitive load.
User feedback.

Key findings.

User testing reveals that "minimalism" must be balanced with "accessible depth". While a clean interface is preferred, the ability to inquire more into specific terminology is a functional requirement when users encounter uncertainty. Furthermore, structural elements like step indicators can negatively impact the experience if they inadvertently create the perception of a longer, more complex process than actually exists. These insights necessitated an iteration on progress visualization to shift the focus toward task momentum in the final high-fidelity version.
Iterations
Balancing Minimalism with Accessible Functional Detail
Users often experience a spike in anxiety or fatigue when they cannot quickly verify their logistics or feel overwhelmed by technical data during the final stages of a booking. Following usability testing, I implemented 3 key component refinements to better align the interface with user mental models:
■ Vehicle Selection: Balancing Visuals with Information

Through usability testing, I observed that participants relied heavily on car visuals but often felt overwhelmed by technical specifications they didn't fully understand. Most users prioritized just three key factors: car type, transmission, and price.
■ My Approach
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‍I streamlined the primary vehicle card to display these essential data points, reducing cognitive load. However, to support power users or those with specific needs, I integrated a "More Details" CTA. This iteration improves the experience by keeping the interface clean while providing an optional "deep dive" for users who require total transparency before committing.
■ Step Indicator: Defining the Path

Testing revealed that a vague progress bar created a perception that the booking process was longer than it actually was, leading to minor user fatigue.
■ My Approach

‍I increased the scale of the step indicator to improve visual prominence and transitioned from a simple line to numbered stages. This change gives users a clear mental map of the journey, letting them know exactly where they are and how many steps remain, which significantly reduces the "perceived length" of the checkout process.
■ Booking Summary: The Verification Safety Net

A critical insight gained during testing was the user's need for a final "sanity check" before payment. I realized that while the flow was functional, it lacked a centralized place to verify the logistical details.
■ My Approach

‍I introduced a dedicated Reservation Details card within the summary page. By consolidating the pickup/drop-off address, dates, and times into one high-visibility component, I created a "safety net" for the user. This ensures they feel confident in their logistics, preventing the "negative perception" or anxiety that often occurs right before a financial commitment.

Global Interaction Enhancements.

Beyond specific components, I implemented several app-wide logic and usability updates to align the interface with actual user behavior and industry best practices.
■ Prioritizing Guest Access

Through competitor usability testing, I observed a consistent friction point: many apps force users to sign up before they can even browse inventory.
Notice how the competing apps lead the user toward clicking "Join," "Sign In," or "Log In" by utilizing prominent brand colors and high-contrast buttons. In comparison, the option to "Continue as Guest" is designed with a relatively smaller font and bland, low-priority colors. This creates a visual hierarchy that pressures the user into an immediate commitment rather than allowing for a low-friction entry into the app.
Since every participant in my study preferred to "Continue as Guest," I made Guest Mode the default experience. By moving the registration option to a secondary button on the homepage, I lowered the barrier to entry, allowing users to reach the core value of the app immediately without upfront commitment.
■ Visual-First Hierarchy

Recognizing that car rental users are highly visual decision-makers, I audited the entire app to ensure images were scaled to an impactful and reasonable size. By prioritizing clear vehicle renders over dense text blocks, I created a more engaging aesthetic that helps users identify their preferred car at a glance, satisfying the behavioral need for visual confirmation seen in the “Browse cars” & “Select a car” phase of the journey map.
Since every participant in my study preferred to "Continue as Guest," I made Guest Mode the default experience. By moving the registration option to a secondary button on the homepage, I lowered the barrier to entry, allowing users to reach the core value of the app immediately without upfront commitment.
■ Progressive Disclosure for Add-ons

The "Packages" and "Extras" pages are traditionally information-heavy, leading to the "overwhelmed" feeling noted in user research. Since most rental add-ons (like GPS or Child Seats) are self-explanatory, I stripped the UI down to titles only. I implemented a “More Details” toggle for each item, which maintains a clean interface for the majority of users while providing full transparency for those who need to inquire further.
Since every participant in my study preferred to "Continue as Guest," I made Guest Mode the default experience. By moving the registration option to a secondary button on the homepage, I lowered the barrier to entry, allowing users to reach the core value of the app immediately without upfront commitment.
■ Navigation Control & Heuristic Alignment

To increase user confidence during the final checkout, I transformed every card on the Booking Summary page into a clickable entry point. This decision was rooted in the Heuristic Evaluation principle of "User Control and Freedom." If a user spots a mistake in their dates or location at the final stage, they can tap the specific card to be directed back to that exact step. This functional enhancement prevents the frustration of "starting over" and ensures a seamless, bidirectional flow.

High Fidelity Prototype.

The high-fidelity prototype serves as the final realization of the user experience, combining validated functional logic with a polished visual identity. By transitioning from wireframes to a complete design, I integrated a refined color palette—including a signature light yellow for map interactions—to establish professional credibility and brand authority.
See full High Fidelity Prototype
The final interactive prototype optimizes every touchpoint—from station confirmation to booking summary. High-fidelity interactions ensure a visually engaging and intuitive experience, specifically engineered to provide users with maximum clarity and transparency throughout the rental process.

Reflection & Final Takeaways.

■ Designing a rental experience highlighted the gap between "standard" industry practices and actual user needs, proving that even small friction points can lead to total abandonment.

■ Reflecting on the process, working on this project gave me a deeper appreciation for the value of user research in guiding design decisions. Taking the time to understand real user pain points helped me stay focused on what mattered most throughout the process. I also understood the importance of testing early and often—getting feedback on my sketches and prototypes helped me catch issues early and improve the experience with each iteration.

■ I learned that global usability is often found in the "unspoken" expectations of the user—such as the freedom to browse without an account or the ability to fix a mistake without losing progress. By applying heuristic principles and information hierarchy, I realized that small logic updates can have a massive impact on user retention. This journey proved that a great experience isn't just about a single component, but how the entire system respects the user's time and autonomy.

■ Overall, this project strengthened my confidence in using a user-centered approach to design thoughtful, practical solutions. It taught me that UX design is a constant balancing act between removing friction and providing enough information to build trust.

Let’s connect.

I’m always looking for new challenges and collaborations. If you’d like to discuss this project further or see how we can work together, feel free to reach out.

Email: Deebot14@gmail.com
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Linkedin: linkedin.com/in/adeeb-graissy

Web & App Design Portfolio: https://adeebs-portofolio-cdcd19.webflow.io/

GitHub: github.com/Deebot14
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